This circuit is from an Electronics World of 1968. The transistors are of the time and the power is supplied with a voltage of 40 V. The circuit is high fidelity.
This shield circuit uses a common CMOS port. The voltage depends on the interfaced logic. The...
Found in 90s 303 Circuits, this circuit is intended for interfacing analog black / white computer...
In this circuit, the LEDs light up in sequence until the last one, when the end of the timing is...