Found in an old Radio Electronics, this circuit applies to frequency meters for frequencies up to 100 MHz. The input impedance is in the order of 1 M ohm.
In fact, the original American publication exaggerated a little about the range that a good...
We found this circuit in an American documentation from the 90s. Through an LED it indicates the...
August 2017 - Mouser Electronics is announcing the availability of TDK ICS-52000 microphones with...