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mprobe model RS-3 part identification
I have an RS-3 that will not read current hen using the clamp mode. It
does work with the test leads though. I posted this a couple of months back and it was suggested that there might be a couple of diodes defective. I disasssembled the unit and the only thing that resembles a diode is a small three terminal device near the bottom of the board with a red dot on one end. Could this possibly be two diodes in series with the cathodes connected together? There are no markings on this device so I'm not sure what it is or if it really is bad. It reads very low resistance in circuit on all terminals. Can someone please help me with this? Thanks, Lenny. |
mprobe model RS-3 part identification
On Sat, 29 Aug 2009 11:46:10 -0700 (PDT),
" put finger to keyboard and composed: I have an RS-3 that will not read current hen using the clamp mode. It does work with the test leads though. I posted this a couple of months back and it was suggested that there might be a couple of diodes defective. I disasssembled the unit and the only thing that resembles a diode is a small three terminal device near the bottom of the board with a red dot on one end. Could this possibly be two diodes in series with the cathodes connected together? There are no markings on this device so I'm not sure what it is or if it really is bad. It reads very low resistance in circuit on all terminals. Can someone please help me with this? Thanks, Lenny. If the device is a diode pair with the central pin being a common anode or cathode, then why would the part require a dot? Such a dual diode would be symmetrical about the centre pin. If the two diodes were in series, then they could be used for ESD protection. The centre pin would be connected to the signal input, the cathode to the positive supply rail, and the anode to the negative rail. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
mprobe model RS-3 part identification
On Aug 30, 2:39*am, Franc Zabkar wrote:
On Sat, 29 Aug 2009 11:46:10 -0700 (PDT), " put finger to keyboard and composed: I have an RS-3 that will not read current hen using the clamp mode. It does work with the test leads though. I posted this a couple of months back and it was suggested that there might be a couple of diodes defective. I disasssembled the unit and the only thing that resembles a diode is a small three terminal device near the bottom of the board with a red dot on one end. Could this possibly be two diodes in series with the cathodes connected together? There are no markings on this device so I'm not sure what it is or if it really is bad. It reads very low resistance in circuit on all terminals. Can someone please help me with this? Thanks, Lenny. If the device is a diode pair with the central pin being a common anode or cathode, then why would the part require a dot? Such a dual diode would be symmetrical about the centre pin. If the two diodes were in series, then they could be used for ESD protection. The centre pin would be connected to the signal input, the cathode to the positive supply rail, and the anode to the negative rail. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Well I would agree that common cathode, (if thats what this is) would seem more conventional in the center, however depending on the layout of the circuit board, I could envision two diodes wired in series, cathode to cathode and the package configured with the cathodes on one side. Also there is no supply in the conventional sense. This is the only component on the board which appears to be an active one. Unless you use the instrument as a wired voltage meter,(a function that does work), with the probes supplied this is basically a clamp type ammeter. Lenny. http://www.byramlabs.com/product_inf...meter%20Analog |
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