Suggested by Radio Electronics from the 90s, this circuit activates a buzzer and an LED when the indicator is activated.
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We found...
This interesting circuit of the American publication Electronics Handbook Volume XIII 1993 shows a...
When the sensor X1 is opened, the relay is energized. When waiting, the current drained is very...