This circuit was found in Ferranti's 1974 transistor manual. The transistors are from the period and the frequencies generated are between 50 Hz and 2 kHz.
This traditional flasher configuration with two transistors drives 5 LEDs with a supply that must...
To operate with high input voltages using a 3-terminal voltage regulator such as the LM340-15, we...
This is the circuit of the commercial Japanese megaphone of the 60s model DM-218. The circuit uses...