We found this circuit in a Hands-On Electronics from the 90s. The circuit must be connected to an external amplifier. Frequency control is capacitive, using an antenna for this purpose
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...