This timer was found in Japanese documentation from the 1960s. The transistor can be replaced by an equivalent and the relay must be of the sensitive type with voltage according to the power supply.
The Texas Instruments TPA3100D2 integrated circuit (www.ti.com) consists of an efficient class D...
This circuit was found in an American documentation on transistors from the 60's. The transistor is made...
Found in a Radio Electronics from the 90s, this circuit generates a 1 kHz signal to serve as a...