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.
Found in Popular Electronics from the 90s, this circuit can employ other low power audio...
We found this circuit in the same publication as the previous one (CB18947E). The circuit uses two...
Found in a manual of integrated circuits from the 90s, this circuit makes use of that time...