The circuit shown consists of a power stage for relay excitation. 2N3053 can be a BD135 and 2N406 can be replaced with a BD136. R3 depends on the trigger voltage.
We found this circuit in a 1987 Hands On Electronics. It was indicated at the time to power...
This amplifier, suggested by National Semiconductor (Now Texas Instruments), has high input...
This circuit causes one LED to light up if the voltage falls below the value set in R3 and the...