This circuit triggers a Sonalarme when the LED used as a sensor receives light. The circuit was found in an old documentation, but the components used are all current.
This circuit generates the busy tone of ordinary telephones. The transistors can be the BC548 and...
This small 1 W amplifier uses a Motorola integrated circuit from the 1970s. The integrated circuit...
This is a configuration widely used for oscillators with crystal from 1 to 20 MHz typically. The...