Designed for the audio track, this circuit was found in a Popular Electronics from the 90's. Other operational can be used and R7 can be 470 k. The frequency is 1 kHz.
We find this circuit in a 1974 Motorola PUTs (Unijunction Programmable Transistors) documentation. The circuit...
This circuit releases a lock only if the correct 4-digit sequence is entered. The circuit uses...
This alternating flasher was found in a 1980s documentation. The transistors may be equivalent such...