We found this circuit in the August 1990 issue of Radio Electronics magazine. The two-digit circuit uses a pressure sensor and is powered by a 9V battery.
This receiver is intended to receive signals from the 6-meter amateur band using only three...
This AM micro-transmitter with power that can reach a few meters is from a publication from the...
The transistor can be the BD135 and this circuit, found in a 1978 publication, can be powered by...