The difference between this circuit and the previous one is that it uses PNP transistors. The circuit is from Radio Electronics magazine from July 1968. The frequency depends on R1 and C1.
This simple circuit, obtained from a Radio Shack documentation, tests transistors and diodes. The...
This simple circuit is intended to test integrated circuits 555 and 741 in 8-pin DIL enclosures. In both...
This is a circuit for receiving signals from the previous transmitter. The circuit uses a common...