My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9 volt
portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch

"hhgggff" wrote in message
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch


You can get simple to use regulator chips that drop the voltage down, you
only need a couple of components to make a working voltage regulator. Ask on
News:sci.electronics.basic - the folk on there are usually very helpful and
should explain all you need.

You can get simple to use regulator chips that drop the voltage down, you
only need a couple of components to make a working voltage regulator. Ask on
News:sci.electronics.basic - the folk on there are usually very helpful and
should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

R

Roger Dewhurst wrote:
You can get simple to use regulator chips that drop the voltage
down, you only need a couple of components to make a working voltage
regulator. Ask on News:sci.electronics.basic - the folk on there are
usually very helpful and should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

A *few* diodes at a couple of ten cents per each. A single 7809 for less
that a $.

In message , rf
writes
Roger Dewhurst wrote:
You can get simple to use regulator chips that drop the voltage
down, you only need a couple of components to make a working voltage
regulator. Ask on News:sci.electronics.basic - the folk on there are
usually very helpful and should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

A *few* diodes at a couple of ten cents per each. A single 7809 for less
that a $.

More like "a *few* diodes at a couple of cents per each".

3V to drop = 5 diodes @ 0.6V per diode. No other circuitry required.
More than good enough for the job.
--
Ian

"Ian Jackson" wrote in message
...
In message , rf
writes
Roger Dewhurst wrote:
You can get simple to use regulator chips that drop the voltage
down, you only need a couple of components to make a working voltage
regulator. Ask on News:sci.electronics.basic - the folk on there are
usually very helpful and should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

A *few* diodes at a couple of ten cents per each. A single 7809 for less
that a $.

More like "a *few* diodes at a couple of cents per each".

3V to drop = 5 diodes @ 0.6V per diode. No other circuitry required. More
than good enough for the job.
--
Ian

The forward conduction knee curve on diodes isn't *that* sharp, depending on
current draw and rating of the diode the drop can be as low as 0.55V and as
high as 1.1V.

"Ian Jackson" wrote in message
...
In message , rf
writes
Roger Dewhurst wrote:
You can get simple to use regulator chips that drop the voltage
down, you only need a couple of components to make a working voltage
regulator. Ask on News:sci.electronics.basic - the folk on there are
usually very helpful and should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

A *few* diodes at a couple of ten cents per each. A single 7809 for less
that a $.

More like "a *few* diodes at a couple of cents per each".

3V to drop = 5 diodes @ 0.6V per diode. No other circuitry required. More
than good enough for the job.

Exactly one 7809 for less than a buck. No other circutry required. Perfect
regulation.

In message , Any one
writes
Ian Jackson wrote on 29-Jul-09 14:40 :
In message , rf
writes
Roger Dewhurst wrote:
You can get simple to use regulator chips that drop the voltage
down, you only need a couple of components to make a working voltage
regulator. Ask on News:sci.electronics.basic - the folk on there are
usually very helpful and should explain all you need.


Why not just drop the voltage through a few diodes? Very simple. Very
cheap.

A *few* diodes at a couple of ten cents per each. A single 7809 for less
that a $.

More like "a *few* diodes at a couple of cents per each".
3V to drop = 5 diodes @ 0.6V per diode. No other circuitry required.

BWHAHAHAHAHAHAHAHA!!!! *cough* *wheeze* *wheeze*

-if- junction temperature remains constant.
-if- load current remains constant.
-if- each selected diode returns precisely 0.6v @ 'load current'.

More than good enough for the job.

AHAHAHAHAHAHAHA!!!

-if- source voltage remains constant
-if- there aren't any ICs that could suffer over-voltage damage
-if- you're as cheap and gullible as a Republi****

lemme guess -- you're a close relative of teh chucktard?

Lemme guess....
You have a degree in Electrical Over-Engineering?
--
Ian

On Sat, 11 Jul 2009 14:33:07 GMT, "hhgggff" wrote:

My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9 volt
portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch


Go to your local radioshack and buy a 9v voltage regulator.
12 volts in 9 volts out. Get a 5 or 3 amp fuse so the player will only
draw the amps it needs.

"richard" wrote in message
...
On Sat, 11 Jul 2009 14:33:07 GMT, "hhgggff" wrote:

My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt
portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch


Go to your local radioshack and buy a 9v voltage regulator.
12 volts in 9 volts out. Get a 5 or 3 amp fuse so the player will only
draw the amps it needs.


Richard

You are implying the fuse will limit the current, which of course it will
not. OK the regulator may have some current limiting in it, but a fuse will
not be much good

--
Bill Naylor
www.electronworks.co.uk
Electronic Kits for Education and Fun

you can only jump a few more lightyears with 12 volt.

"hhgggff" wrote in message
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch

"hhgggff" wrote in
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery,
we now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

The tape motor will run at the wrong speed for one. What you need is a
voltage regulator. A 7809 should do the trick. The 7800 series convert DC
voltages. Granted a transformer does it, but these handle *much* wider
voltage inputs and are tiny in comparison. A 7812 hooked to the +12v
connection with the other connection hooked to a 200 microfarad capacitor
should give you a rock solid +9v out. You'll need a piece of breadboard
about 1" square to mount these on.

http://en.wikipedia.org/wiki/78xx

--
(setq (chuck nil) car(chuck) )

"chuckcar" wrote in message
...
"hhgggff" wrote in
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery,
we now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

The tape motor will run at the wrong speed for one. What you need is a
voltage regulator. A 7809 should do the trick. The 7800 series convert DC
voltages. Granted a transformer does it, but these handle *much* wider
voltage inputs and are tiny in comparison. A 7812 hooked to the +12v
connection with the other connection hooked to a 200 microfarad capacitor
should give you a rock solid +9v out. You'll need a piece of breadboard
about 1" square to mount these on.


You should read up on a subject you know little about before giving advice
to others.

Even in older cassette recorders the motors had centrifugal speed governors
and modern ones have an IC speed controller (otherwise they'd run slower and
slower as the battery was used).

Your mention of transformers is misleading, without a "chopper" circuit to
convert DC into AC a transformer will burn out.

The OP is best advised to ask people who are equipped to give accurate
advice, such as the folk on News:sci.electronics.basics .

"ian field" wrote in
:


"chuckcar" wrote in message
...
"hhgggff" wrote in
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery,
we now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

The tape motor will run at the wrong speed for one. What you need is a
voltage regulator. A 7809 should do the trick. The 7800 series convert
DC voltages. Granted a transformer does it, but these handle *much*
wider voltage inputs and are tiny in comparison. A 7812 hooked to the
+12v connection with the other connection hooked to a 200 microfarad
capacitor should give you a rock solid +9v out. You'll need a piece of
breadboard about 1" square to mount these on.


You should read up on a subject you know little about before giving
advice to others.

Considering the fact that my post is *far* more detailed than yours,
you're hardly a person to make such a judgement = along with your errors
detaied below.

Even in older cassette recorders the motors had centrifugal speed
governors and modern ones have an IC speed controller (otherwise they'd
run slower and slower as the battery was used).

And none of this would burn out with 1 1/3 times the voltage input?
dubious.

Your mention of transformers is misleading, without a "chopper" circuit
to convert DC into AC a transformer will burn out.

He's *using* a DC power source - a car battery. So a rectifier circuit or
an analogue is completely unncessary

The OP is best advised to ask people who are equipped to give accurate
advice, such as the folk on News:sci.electronics.basics .

One *minor* correction of my post however - that *should* have been a 7809
not a 7812. This I picked up immediately when I read your reply. A pretty basic
error you didn't even notice. a 7812 converts *to* 12v whereas a 7809 converts
to 5v. Hence their names.

--
(setq (chuck nil) car(chuck) )

On Sat, 11 Jul 2009 21:50:55 +0000 (UTC), chuckcar
wrote:

"ian field" wrote in
:


"chuckcar" wrote in message
...
"hhgggff" wrote in
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery,
we now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

The tape motor will run at the wrong speed for one. What you need is a
voltage regulator. A 7809 should do the trick. The 7800 series convert
DC voltages. Granted a transformer does it, but these handle *much*
wider voltage inputs and are tiny in comparison. A 7812 hooked to the
+12v connection with the other connection hooked to a 200 microfarad
capacitor should give you a rock solid +9v out. You'll need a piece of
breadboard about 1" square to mount these on.


You should read up on a subject you know little about before giving
advice to others.

Considering the fact that my post is *far* more detailed than yours,
you're hardly a person to make such a judgement = along with your errors
detaied below.

---
The fact that your post was more "detailed" than Ian's doesn't mean that
his was wrong.
---

Even in older cassette recorders the motors had centrifugal speed
governors and modern ones have an IC speed controller (otherwise they'd
run slower and slower as the battery was used).

And none of this would burn out with 1 1/3 times the voltage input?
dubious.

---
Just conjecture without knowing more about the cassette recorder.
---

Your mention of transformers is misleading, without a "chopper" circuit
to convert DC into AC a transformer will burn out.

He's *using* a DC power source - a car battery. So a rectifier circuit or
an analogue is completely unncessary

---
But, since his application runs on DC, your reference to a transformer
was misleading since a transformer takes an AC input and supplies an AC
output which must then be rectified, filtered, and possibly regulated
before it can be used by the DC input device.

If, by "transformer", you meant an AC to DC converter, then your
terminology was wrong.
---

The OP is best advised to ask people who are equipped to give accurate
advice, such as the folk on News:sci.electronics.basics .

One *minor* correction of my post however - that *should* have been a 7809
not a 7812. This I picked up immediately when I read your reply. A pretty basic
error you didn't even notice. a 7812 converts *to* 12v whereas a 7809 converts
to 5v. Hence their names.

---
???

A 7809 converts to 9V, not 5V.

In addition, not knowing the current requirements of the recorder, your
comment to build it on one square inch of breadboard (perfboard?) may
well be inconsistent with the heat-sinking required for the regulator.

And why the 200µF capacitor?

Why not 10?

Why not 1000?

JF

snip


A 7809 converts to 9V, not 5V.

In addition, not knowing the current requirements of the recorder, your
comment to build it on one square inch of breadboard (perfboard?) may
well be inconsistent with the heat-sinking required for the regulator.

And why the 200µF capacitor?

Why not 10?

Why not 1000?

JF


Forget the regulator. Connect 4 diodes in series with the power supply and
that will get you into the ballpark. Just make sure the diodes can handle
the max current the thing will draw.

John Fields wrote in
:

On Sat, 11 Jul 2009 21:50:55 +0000 (UTC), chuckcar
wrote:

"ian field" wrote in
:


"chuckcar" wrote in message
...
"hhgggff" wrote in
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car
battery, we now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old
9 volt portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

The tape motor will run at the wrong speed for one. What you need is
a voltage regulator. A 7809 should do the trick. The 7800 series
convert DC voltages. Granted a transformer does it, but these handle
*much* wider voltage inputs and are tiny in comparison. A 7812 hooked
to the +12v connection with the other connection hooked to a 200
microfarad capacitor should give you a rock solid +9v out. You'll
need a piece of breadboard about 1" square to mount these on.


You should read up on a subject you know little about before giving
advice to others.

Considering the fact that my post is *far* more detailed than yours,
you're hardly a person to make such a judgement = along with your errors
detaied below.

---
The fact that your post was more "detailed" than Ian's doesn't mean that
his was wrong.
---

Even in older cassette recorders the motors had centrifugal speed
governors and modern ones have an IC speed controller (otherwise
they'd run slower and slower as the battery was used).

And none of this would burn out with 1 1/3 times the voltage input?
dubious.

---
Just conjecture without knowing more about the cassette recorder.
---

Your mention of transformers is misleading, without a "chopper"
circuit to convert DC into AC a transformer will burn out.

He's *using* a DC power source - a car battery. So a rectifier circuit
or an analogue is completely unncessary

---
But, since his application runs on DC, your reference to a transformer
was misleading since a transformer takes an AC input and supplies an AC
output which must then be rectified, filtered, and possibly regulated
before it can be used by the DC input device.

If, by "transformer", you meant an AC to DC converter, then your
terminology was wrong.
---

The OP is best advised to ask people who are equipped to give accurate
advice, such as the folk on News:sci.electronics.basics .

One *minor* correction of my post however - that *should* have been a
7809 not a 7812. This I picked up immediately when I read your reply. A
pretty basic error you didn't even notice. a 7812 converts *to* 12v
whereas a 7809 converts to 5v. Hence their names.

---
???

A 7809 converts to 9V, not 5V.

Message-ID:

In addition, not knowing the current requirements of the recorder, your
comment to build it on one square inch of breadboard (perfboard?) may
well be inconsistent with the heat-sinking required for the regulator.

And why the 200µF capacitor?

Why not 10?

Too small to absorb the variations

Why not 1000?

Way too big for the voltage.

--
(setq (chuck nil) car(chuck) )

I will look into a voltage regulator but will probably just get an old car
stereo as it's easier

tafankuverymuch

"hhgggff" wrote in message
news
My friends dad is building a Tardis for his grandson.

We have rigged up the blue flashing light using a 12 volt car battery, we
now need to sort out the sounds.

I was thinking of using an old cars cassette tape, but I have an old 9
volt
portable cassette handy.

Will it burn down the TARDIS if I use that instead ?

tafankuverymuch


If the old player isnt that important, just wire it up and see what happens
..
Worst case is that your throwing away something that probably shoulda been
discarded years ago anyhow..
If it just plays too fast then you can make a slower recording ;P..


http://www.national.com/mpf/LM/LM2575.html
throw in a diode, inductor, couple of caps, and a variable resistor and you
have a up to 1amp source :/..
Course, it might just be cheaper and easier to find some crappy used phone
charger or something that has a output close to 9v ..

I was thinking of using an old cars cassette tape, but I have an old 9
volt
portable cassette handy.

Well, In the end I just plugged it in and it works,correct speed.

tafankuverymuch

"hhgggff" wrote in message
om...

I was thinking of using an old cars cassette tape, but I have an old 9
volt
portable cassette handy.

Well, In the end I just plugged it in and it works,correct speed.

tafankuverymuch

If you're running a 9V cassette player from a car battery, don't run it at
full volume - the audio output might be the weak link.