| Products > Test Equipment |
| Keithley Sourcemeter DIGOUT Protection ? |
| (1/1) |
| JohnPi:
The Keithley Sourcemeters (e.g. 2400) have digital output pins -- DIGOUT. This is shown in the manual as suitable for driving a relay, but no protection against coil inductive spikes is shown. Does it not have protection ? Do I have to add my own diode ? |
| gamalot:
The diode in the picture (in series with a resistor) is probably what you're expecting, maybe they've drawn the diode's polarity reversed. :-// --- Sorry I looked again, that diode and resistor should be for pull-up the output. |
| Kleinstein:
The diode to protect from the inductive kickback of the relay should be at the relay. If in doubt add a 2nd diode - it does not hurt. |
| JohnPi:
No, that diode is probably to prevent an external > 5 V signal from damaging the internal 5 V supply by pulling it up. I'll have to add external diodes to clamp the inductance. |
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