We found this circuit in the December 1968 issue of Radio Electronics magazine. The circuit is used with high-impedance magnetic headphones. The transistors are from that time.
Found in Radio Electronics from the 90s, this circuit uses a thermistor as a sensor that can have...
The scale of this scale uses LEDs, and its accuracy depends on the number of LEDs. We found this...
Found in American documentation from the 90s, this circuit generates sound bursts according to the...