This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
STMicroelectronics MP23AB02B MEMS Audio Sensor is a compact, low-power microphone built with a...
This basic configuration can be found in a lot of articles on this site. In this case, the relay...
The circuit shown bellow is na áudio amplifier using Darlington transistor in a complementary...