This 5 V power supply for TTL, Shields and microcontrollers is old, and the components can be replaced by modern equivalents. Transistor Q1 can be a TIP31 and Q2 can be a BD135.
This variable voltage reference uses a Norton operational amplifier. The voltage is adjusted at...
This 6 transistor TR26 commercial radio was sold in Japan in the 60s. It is a super heterodyne circuit...
n be assembled with BC558 transistors for low power transistors and a BD136 for the output. The...