This circuit is from an 80's documentation, firing when the input voltage exceeds 5 V. The SCR can be the TIC106 need not have a heatsink.
Found in an American documentation from the 90s, this sophisticated circuit is suitable for...
This Wheatstone bridge has a thermistor or NTC sensor, allowing the measurement of temperatures by...
This circuit shows how to get 5 V under low current from an operating amplifier 741. I got this...