This circuit is from a Radio Electronics from February 1959. The circuit has a speaker output and good sensitivity. Power is supplied from a 9 V battery.
The coil is formed by 70 + 5 turns of 6 to 30 AWG wire on a 1 cm to 10 cm ferrite core. The...
We find this encoding circuit in an American 1980s amateur radio documentation. The circuit can be...
This low-noise, low-drift amplifier was found in a 90's EDN. It can be implemented with modern...