This is part of my readout electronics system.
This is one of the oldest modules I built that I haven’t desoldered so far. It is an analog threshold relay with voltage reference and amplification.
There is a 10V reference voltage feeding into the 10-turn potentiometer on the front panel, this selects the threshold voltage. A lever switch selects whether the input signal is amplified by x10 or just passed through to the comparator. The comparator (LM358) itself is a window comparator where another lever switch selects whether to take the trigger signal from the under- or over voltage outputs. The selected output then triggers a relay. The LED on the front panel is dual-color (R-G), where red indicates that the unit has triggered and green indicates that the unit is powered and ready.
There is a manual test button that instantaneously triggers the relay, this can be used to test any connected circuits for proper function, without having to take the unit out of service.
