This small transmitter appeared in the March 1989 issue of Radio Electronics magazine. The two-transistor circuit used an electret microphone and had a range of a few dozen meters.
This circuit was obtained in a 1969 Mullard manual. The transistors are from that time. The input...
This circuit with the PLL4046 was found in the October 1994 Electronics Now magazine. The...
This circuit was found in a 90s Hands-On Electronics. When a signal appears at the headphone...