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.
In the figure we have an RS flip-flop made with two operational transconductance amplifiers. The circuit...
This circuit is from the 1993 Linear Technology Applications. We can implement the same oscillator...
This circuit indicates when the monitored voltage drops below the value determined by the divider...