This circuit was found in an American documentation two years 80. The MOSFET is of double port, difficult to obtain now and the circuit has a tuning frequency determined by RC.
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...