This high-gain circuit was found in an American publication from the 1990s. The circuit can use general purpose transistors and powered from a source or battery.
The CMOS 4046 integrated circuit is not very common today, consisting of a very efficient PLL for...
This circuit turns on an old cassette recorder when the telephone rings, thus enabling the...
This circuit can be used in panel signaling with common incandescent lamp. The lamp will flash at a...