This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
Pressing and releasing S1 remains one of the neon lamps. Which one will be, it is not possible to...
This circuit, which appears on our website in different versions, uses an integrated VU which is...
This VCA was found in the July 1988 issue of Radio Electronics magazine. It uses an OTA op amp and...