relay coil inductance
I haven't done a relay driver circuit for, literally, eons.
Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
relay coil inductance
On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson
wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF |
relay coil inductance
On Sat, 05 Sep 2009 12:48:41 -0500, John Fields
wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF I'll have my customer measure one ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
relay coil inductance
On Sat, 05 Sep 2009 12:48:41 -0500, John Fields
wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. |
relay coil inductance
On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life
wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF |
relay coil inductance
On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote:
On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? -- www.wescottdesign.com |
relay coil inductance
On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life
wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Probably, Jim is designing an IC where every 'square' or 'hex' counts. So maybe he doesn't want to use more than he has to? Just a thought. Jon |
relay coil inductance
On Sat, 05 Sep 2009 13:22:37 -0500, John Fields
wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF What would NymNoNuts know? [pause:burp: "Croque Madame" & orange-almond salad for lunch :-] I'm working with an X-Fab BiCMOS process... nominally 5.5V max (7V absolute max). Can't use a "flyback" diode... any "diode" will induce destructive substrate currents. So I'm using an old design trick of mine from "eons" ago... active device turn-on to limit "flyback". So I need the inductance to estimate device sizes. What would NymNoNuts know? Heaven help us, but I estimate he's a technician in our "defense" industry :-( ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The REAL reason Obama and the DemocRATs want control of the Internet is that it's too good a tool for freedom,keeping them from implementing their communist agenda. -Jim Yanik 8/28/2009 |
relay coil inductance
On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott
wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Dead-on, Tim! ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | "Minimum wage" is why all our manufacturing is in Mexico and China The only things "Made in America" are beer and prostitutes |
relay coil inductance
On Sat, 05 Sep 2009 13:22:37 -0500, John Fields
wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF 3.3 V relay that requires a can over it due to the field it makes? I suppose it is possible. I doubt much field is generated though. The collapsing field gets pumped into the diode. One could design the firing circuit to "slow stop" as well. reducing any collapsing flux to minimal since it is created as a result of the slew rate at which it was collapsed. |
relay coil inductance
On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott
wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. |
relay coil inductance
On Sat, 05 Sep 2009 12:33:59 -0700, Jim Thompson
wrote: What would NymNoNuts know? What would a retard that replies the way you do know? |
relay coil inductance
On Sat, 05 Sep 2009 12:33:59 -0700, Jim Thompson
wrote: Can't use a "flyback" diode... any "diode" will induce destructive substrate currents. You should not fire them directly from the chip. They should ALL incorporate a driver AFTER the chip for each one. Diodes have been placed across the coils of relays for decades. There is a reason for that. The diode CLAMPS current, keeping it from the driver, idiot! So I'm using an old design trick of mine from "eons" ago... active device turn-on to limit "flyback". The flyback occurs at turn off, NOT turn on, idiot, and the diode is ONLY in play during turn off events, and is specifically for clamping that flyback event. So I need the inductance to estimate device sizes. I think you are in overkill mode. What would NymNoNuts know? Likely far more than you. Heaven help us, but I estimate he's a technician in our "defense" industry :-( That is another one of your problems. Your capacity to make a valid estimation died twenty years ago, and your capacity to make one in your senile condition is even less than it was when you were not senile. Even then, it was marginal, at best. |
relay coil inductance
On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson
wrote: Dead-on, Tim! ...Jim Thompson Relay opening time on a mechanical relay is NOT electrically related. It is mechanical. You can slow it down electrically, but there is nothing you can do that makes the event occur any faster. |
relay coil inductance
On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson
wrote: On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Dead-on, Tim! ...Jim Thompson Like this... http://www.analog-innovations.com/SE...elayDriver.pdf In the discrete world, with more voltage tolerance available, you can scale this to larger controlled flyback potentials, for fast turn-off. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | California is a truly beautiful state. Too bad it's been so thoroughly ****ed over by liberals. |
relay coil inductance
Archimedes' Lever wrote:
On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson wrote: Dead-on, Tim! ...Jim Thompson Relay opening time on a mechanical relay is NOT electrically related. It is mechanical. You can slow it down electrically, but there is nothing you can do that makes the event occur any faster. Do you think that, with a diode across the relay to reduce the flyback voltage spike, that slow-er decaying current, and its associated magnetic field holding the relay in, does NOT slow down the relay opening ??? boB |
relay coil inductance
On Sat, 05 Sep 2009 13:45:22 -0700, life imitates life wrote:
On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. That sounds like a bureaucrat's version of "immediate". A relay will _always_ turn off with some delay, first for the magnetic field to die down, then for the contacts to physically move. Even if you don't care about turning off the magnetic field as fast as possible, if you don't size your snubber circuit right the coil will take out your output driver when you try to turn off the current. -- www.wescottdesign.com |
relay coil inductance
On 5 Sep 2009 17:46:01 -0500, boB wrote:
Archimedes' Lever wrote: On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson wrote: Dead-on, Tim! ...Jim Thompson Relay opening time on a mechanical relay is NOT electrically related. It is mechanical. You can slow it down electrically, but there is nothing you can do that makes the event occur any faster. Do you think that, with a diode across the relay to reduce the flyback voltage spike, that slow-er decaying current, and its associated magnetic field holding the relay in, does NOT slow down the relay opening ??? boB NymNoNuts has no CLUE ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
relay coil inductance
On Sat, 05 Sep 2009 17:54:23 -0500, Tim Wescott
wrote: On Sat, 05 Sep 2009 13:45:22 -0700, life imitates life wrote: On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. That sounds like a bureaucrat's version of "immediate". A relay will _always_ turn off with some delay, first for the magnetic field to die down, then for the contacts to physically move. Even if you don't care about turning off the magnetic field as fast as possible, if you don't size your snubber circuit right the coil will take out your output driver when you try to turn off the current. "life imitates life"... as defined by yet another persona of NymNoNuts (and caught by my filters)... doesn't have a clue about coil energy that has to go somewhere. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Postings via gmail, yahoo, hotmail, aioe, uar or googlegroups, and trolls/feeders, are now automatically kill-filed using Agent v5.0 To be white-listed, send request via the E-mail icon on my website |
relay coil inductance
On 5 Sep 2009 17:46:01 -0500, boB wrote:
Archimedes' Lever wrote: On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson wrote: Dead-on, Tim! ...Jim Thompson Relay opening time on a mechanical relay is NOT electrically related. It is mechanical. You can slow it down electrically, but there is nothing you can do that makes the event occur any faster. Do you think that, with a diode across the relay to reduce the flyback voltage spike, that slow-er decaying current, and its associated magnetic field holding the relay in, does NOT slow down the relay opening ??? boB The coil's flux collapses and creates a spike. The diode clamping that spike does NOT slow the spring loaded return time of the plate which is attached to the contact(s) as it pulls away from the solenoid core end face. So, the answer is NO. The magnetic field is collapsing, as in NOT "holding in" the relay any longer. The plate begins to pull away as soon as the power is removed, and the clamping diode does nothing to slow that process. The field is collapsing, not being splayed out. There is no longer an attachment force as soon as the power is removed. The collapsing flux induces a current though the diode, but that diode does NOT slow the collapse rate. That rate was determined by the slew rate of the voltage change which was full voltage to zero in a practically square wave fall rate. The collapsing flux makes the back EMF. The diode eats that current. The plate has already been released long before those events. Diode or not, the relay opens at the same rate. The diode is there to kill the spike, and that is all. To slow the process, one needs to slow the rate at which the excitation voltage falls. Once it falls below a certain value, however, the relay will STILL "snap" open, so even that method does not "slow" things much. Speeding one up, however, is what the engineers that designed it did. I doubt you will be able to improve on their works short of adding a solenoid to pull the relay off faster than the mechanical spring does. A push-pull relay where there are two solenoids operating it. Otherwise, you are simply tied to the mechanics of the system. |
relay coil inductance
On Sat, 05 Sep 2009 17:54:23 -0500, Tim Wescott
wrote: On Sat, 05 Sep 2009 13:45:22 -0700, life imitates life wrote: On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. That sounds like a bureaucrat's version of "immediate". More ****ing retarded bull**** from someone with no real argument that is based in fact. A relay will _always_ turn off with some delay, No ****, you retarded ****. It was *I* that said that you can slow the opening, but will fail to make it faster than it already is. first for the magnetic field to die down, Wrong. The closure plate begins to pull away as soon as the excitation voltage is removed. A static field pulls in and holds the plate, a collapsing field does not. then for the contacts to physically move. That is a function of how far BEFORE the plate closure point they MAKE contact. They will always make contact before the plate is fully clasped. They will always remain in contact as the plate pulls away, until it reaches a specific point of opening. Even if you don't care about turning off the magnetic field as fast as possible, First it has to matter. Nearly all designers remove excitation voltage immediately. That means the field is removed immediately. That is also what causes the spike. if you don't size your snubber circuit right the coil will take out your output driver when you try to turn off the current. That is what the diode is for. There will be no current any further back in the circuit if the diode does its job. |
relay coil inductance
On Sat, 05 Sep 2009 16:11:16 -0700, Jim Thompson
wrote: doesn't have a clue about coil energy that has to go somewhere. ...Jim Thompson Lighting your retarded ass up with a few fibrillation inducing jolts is well within the realm of my knowledge, and proves yet again that you have no clue about that which you spew. Of course **** is not all that conductive, so I might have to up the juice quite a bit to have an effect on you. pasticcio |
relay coil inductance
On Sat, 05 Sep 2009 16:46:43 -0700, life imitates life
wrote: On Sat, 05 Sep 2009 16:11:16 -0700, Jim Thompson wrote: doesn't have a clue about coil energy that has to go somewhere. ...Jim Thompson Lighting your retarded ass up with a few fibrillation inducing jolts is well within the realm of my knowledge, and proves yet again that you have no clue about that which you spew. Of course **** is not all that conductive, so I might have to up the juice quite a bit to have an effect on you. pasticcio Not to mention the hard as rock heart, if there is even one there. |
relay coil inductance
"boB" wrote in message ... Archimedes' Lever wrote: On Sat, 05 Sep 2009 12:43:20 -0700, Jim Thompson wrote: Dead-on, Tim! ...Jim Thompson Relay opening time on a mechanical relay is NOT electrically related. It is mechanical. You can slow it down electrically, but there is nothing you can do that makes the event occur any faster. Do you think that, with a diode across the relay to reduce the flyback voltage spike, that slow-er decaying current, and its associated magnetic field holding the relay in, does NOT slow down the relay opening ??? boB Here's a pretty good pdf with explanation of different spike suppresion methods. It lists drop out times for the different methods, for one particular relay and values. http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf PS. A diode is the slowest dropout time listed. Mike |
relay coil inductance
On Sat, 5 Sep 2009 20:35:02 -0500, "amdx" wrote:
Here's a pretty good pdf with explanation of different spike suppresion methods. It lists drop out times for the different methods, for one particular relay and values. http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf PS. A diode is the slowest dropout time listed. Mike Note also that the diode is also the best at suppressing the spike. Note also that UNsupressed is the only way to get it fast. ALL the other methods slow it. ALL of the other methods violate his 'issues' list. In many cases, that is the most important constraint (the spike). Note also that all the figures are for 12V relays, which are not in much use on modern low voltage circuit designs these days. I am quite certain that any 3.3V relay you choose to examine will prove to be faster than any of the numbers that more than 10 year old document measured. Even the diode. |
relay coil inductance
Jim Thompson wrote:
I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! ...Jim Thompson Who cares? Just use the standard RC snubber across the coil; 100 ohms should be fine. |
relay coil inductance
On Sat, 05 Sep 2009 16:11:16 -0700, Jim Thompson wrote:
On Sat, 05 Sep 2009 17:54:23 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 13:45:22 -0700, life imitates life wrote: On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. That sounds like a bureaucrat's version of "immediate". A relay will _always_ turn off with some delay, first for the magnetic field to die down, then for the contacts to physically move. Even if you don't care about turning off the magnetic field as fast as possible, if you don't size your snubber circuit right the coil will take out your output driver when you try to turn off the current. "life imitates life"... as defined by yet another persona of NymNoNuts (and caught by my filters)... doesn't have a clue about coil energy that has to go somewhere. ...Jim Thompson I thought that maybe Phil had assumed a pseudonym, but this guy is less knowledgeable both in electronics and vile language. -- www.wescottdesign.com |
relay coil inductance
On Sun, 06 Sep 2009 01:36:53 -0500, Tim Wescott
wrote: On Sat, 05 Sep 2009 16:11:16 -0700, Jim Thompson wrote: On Sat, 05 Sep 2009 17:54:23 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 13:45:22 -0700, life imitates life wrote: On Sat, 05 Sep 2009 14:01:59 -0500, Tim Wescott wrote: On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. Jim designs custom IC's, so (I assume) he's concerning himself with it so he can make the output stage of his circuit both economical and robust. He may even care about making the relay turn off quickly. It seems like a perfectly valid concern to me, even if the circuit in question _isn't_ custom -- what if you're powering the relay from logic, and want to insure fast & safe turn-off? Turn off can be immediate. The contacts open before the solenoid completes opening to the gap it was at when off. That sounds like a bureaucrat's version of "immediate". A relay will _always_ turn off with some delay, first for the magnetic field to die down, then for the contacts to physically move. Even if you don't care about turning off the magnetic field as fast as possible, if you don't size your snubber circuit right the coil will take out your output driver when you try to turn off the current. "life imitates life"... as defined by yet another persona of NymNoNuts (and caught by my filters)... doesn't have a clue about coil energy that has to go somewhere. ...Jim Thompson I thought that maybe Phil had assumed a pseudonym, but this guy is less knowledgeable both in electronics and vile language. All the pussy that you are is doing is looking to get a rise out of me. That only amounted to me chuckling at the depth of your stupidity. |
relay coil inductance
On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson
wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! ...Jim Thompson 22. it is. |
relay coil inductance
On Sat, 05 Sep 2009 22:28:38 -0700, Robert Baer
wrote: Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! ...Jim Thompson Who cares? Just use the standard RC snubber across the coil; 100 ohms should be fine. You should learn to read... it's a custom chip issue. I posted a link to a proper solution. BTW, 100 Ohms and a coil current of 33mA would produce 6.6V (net, 3.3V supply) on the drain, exceeding the 5.5V maximum operating rating. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
relay coil inductance
"John Fields" wrote in message ... On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Or buy a peak Atlas LCR meter and measure it. |
relay coil inductance
"John Fields" wrote in message ... On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. |
relay coil inductance
"ian field" wrote in message ... "John Fields" wrote in message ... On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Probably this one? http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf Note, life imitates life finds no wisdom in a ten year old document. Mike |
relay coil inductance
On Sun, 6 Sep 2009 16:17:09 +0100, "ian field"
wrote: "John Fields" wrote in message .. . On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. --- I remember it too, but I don't remember where I found it. The gist of it, as I recall, was that the higher the back EMF is allowed to rise before it's clamped, the faster the relay will open. JF |
relay coil inductance
On Sun, 6 Sep 2009 16:17:09 +0100, "ian field"
wrote: "John Fields" wrote in message .. . On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Ian, Did you miss seeing this... http://www.analog-innovations.com/SE...elayDriver.pdf A little better than a flyback diode, and no destructive currents running in my substrate ;-) I had to conjure that up from memory... first done so long ago (BC: before CAD), it only exists somewhere in my paper archives ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
relay coil inductance
On Sun, 6 Sep 2009 16:17:09 +0100, "ian field"
wrote: "John Fields" wrote in message .. . On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Diode+resistor or diode+zener are both a lot faster than just a diode. Or even just a series or shunt resistor, if you can spare the power. No clamp at all is even faster; just let it fly up and ring, with suitable precautions. The untimate would be to apply a large reverse voltage to the coil until the current goes to zero. That's what happens automagically in a linear amp driving an inductive load with current feedback. Reeds are usually pretty lossy, lots of coil resistance, so may be OK with just a diode. But they are terrible gadgets in general. In my experience, they are nowhere near as reliable as claimed, and they bounce/twang forever. John |
relay coil inductance
On Sun, 6 Sep 2009 10:28:46 -0500, "amdx" wrote:
"ian field" wrote in message ... "John Fields" wrote in message ... On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Probably this one? http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf Note, life imitates life finds no wisdom in a ten year old document. Mike Show me where that was ever stated, you fact morphing retard! |
relay coil inductance
On Sun, 06 Sep 2009 09:37:55 -0700, John Larkin
wrote: On Sun, 6 Sep 2009 16:17:09 +0100, "ian field" wrote: "John Fields" wrote in message . .. On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Diode+resistor or diode+zener are both a lot faster than just a diode. Or even just a series or shunt resistor, if you can spare the power. No clamp at all is even faster; just let it fly up and ring, with suitable precautions. The untimate would be to apply a large reverse voltage to the coil until the current goes to zero. That's what happens automagically in a linear amp driving an inductive load with current feedback. Reeds are usually pretty lossy, lots of coil resistance, so may be OK with just a diode. But they are terrible gadgets in general. In my experience, they are nowhere near as reliable as claimed, and they bounce/twang forever. --- Mercury wetted don't. JF |
relay coil inductance
"amdx" wrote in message ... "ian field" wrote in message ... "John Fields" wrote in message ... On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Probably this one? http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf Note, life imitates life finds no wisdom in a ten year old document. That's not the one I was thinking of, it was probably a Tyco appnote. |
relay coil inductance
"life imitates life" wrote in message ... On Sun, 6 Sep 2009 10:28:46 -0500, "amdx" wrote: "ian field" wrote in message ... "John Fields" wrote in message ... On Sat, 05 Sep 2009 11:03:51 -0700, life imitates life wrote: On Sat, 05 Sep 2009 12:48:41 -0500, John Fields wrote: On Sat, 05 Sep 2009 09:41:06 -0700, Jim Thompson wrote: I haven't done a relay driver circuit for, literally, eons. Where do I look for reed relays that work on 3.3V supplies with specications for the coil inductance? Thanks! --- That's a toughie. I can't recall ever seeing inductance data on a spec sheet; I think you'll probably have to go to the manufacturer for that one. JF Would not the real question be why would someone concern himself with the solenoid inductance of a miniature relay? I could see it if it were huge. --- L di E= ------, dt so the diode damping the "spark" when the driver went open would slow down the opening of the contacts, maybe? Or maybe the magnetic field building up and breaking down might affect some nearby component? Dunno... JF ISTR an appnote floating about on the net that recommends using a combination of diode and zener to clamp the back emf, apparently if you just clamp it with a single diode, the back emf drives a current round the diode/solenoid circuit which causes hesitant unlatching. Probably this one? http://www.kilovac.com/appnotes/app_pdfs/13c3311.pdf Note, life imitates life finds no wisdom in a ten year old document. Mike Show me where that was ever stated, you fact morphing retard! Quote from life imitates life, " I am quite certain that any 3.3V relay you choose to examine will prove to be faster than any of the numbers that more than 10 year old document measured. Even the diode." Just doesn't seem like you saw a lot of wisdom in the 10 your old document. Tell me, what part of it do you think is wise? I didn't morph and I'm not a retard, I think your losing your mind. Mike |
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