Found in an Electronic Design from the 90's, this circuit measures the equivalent resistance in series of a resistor. The circuit operates at 50 kHz producing a rectangular signal.
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...