Other Parts Discussed in Thread: LM324, LM324-N
Hi Guys,
I need your help. We are having some trouble with the op-amp, negative input going low impedance and I’m don’t know why this might be happening.
The circuit is shown below. The input signal can be anywhere between 0 and 24V.
I’m not sure if we have a doggy batch or I’m doing something very wrong that I can’t see.
When the device dies the inputs don’t work anymore at the connector side, but if you apply a voltage to say D7 anode, 5V the output switches okay.
I’m sort of presuming the catch diode is damaged. I personally cant see anything wrong with the circuit.
If you measure across the 100K when the device is damaged it measure 3K even with the ~~100k removed.
Any advice?
Kind regards
Rich