This simple logic level tester was found in Radio Electronics from the 90s. The inverters are of the 4009 type and the power comes from the circuit being analyzed.
circuit is used to increase the sensivity of a relay. A 50 to 100 mA relay can be triggered with...
The configuration shown makes use of a simple source and the gain is given by the relationship between R3...
This blinker consists of a simple multivibrator and instead of the lamp, an LED and a 470 ohms...