It actually consists of a tunable field strength meter. The circuit is of an old documentation and the circuit must be tuned to the frequency to be monitored. The circuit offers the option to use a headset.
This sensitive touch key appears on this website from other sources. This version was taken from a...
This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used...
CMOS 4046 (PLL) is not very common. In this circuit it generates short pulses to excite a high...