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.
This is an old circuit with a feature that most modern oscilloscopes have. We found it in a Radio...
This circuit was found on an 80's Ham Radio. The transistor admits equivalent. The circuit can...
This amplifier, suggested by National Semiconductor, is characterized by its very high input...