This small tone generator was found in the November 1987 issue of Radio Electronics magazine. The phototransistor is common and controls the sounds generated. The basic frequency is given by C1.
This signal booster that ranges from long waves to about 30 MHz is recommended to be used with...
TTL square signals can be divided by 10 using this circuit. The maximum frequency depends on the...
Used in 1950s CW receivers, this type of circuit used germanium transistors. The circuit has...