This circuit was obtained from a Philips documentation from 1968. The transistors can be replaced with equivalents, only with care so that the doubles are exchanged for matched pairs.
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...