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 setting appears other times in this section from other sources. This is from an 80's American...
This digital timer provides timings from 1 minute to 10 hours with indication on a 3-digit...
Signals from 27 MHz to 150 MHz can be produced by this one-transistor oscillator. The frequency...