We found this circuit in a 1964 Electronic Design. Transistors can be modern general-purpose equivalents. The circuit converts a 1 MHz sinusoidal signal into a rectangular signal.
This circuit shows how to use an LED as a photodiode controlling a signaling LED. As the LEDs can...
This circuit was obtained in a 1969 Mullard manual. The transistors are from that time. The input...
This alarm does not interrupt its operation when the power is cut. A battery is kept at a constant...