This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is suitable for detecting explosions, distant echoes and seismic vibrations.
This antenna for the frequencies 146 or 440 MHz was found in a magazine 73 for Amateur Radio of...
This circuit produces 1 kHz square signals using the CMOS IC 4070. The frequency is given by the...
Found in a 90s PE Hobbyst Handbook, this circuit mimics the sound of a space gun. The components...