This RF amplifier step has a dynamic range of 140 dB and can amplify signals from 0.5 to 40 MHz. FET is old, but modern equivalents can be used.
This application consists of a circuit that trips when the sensor resistance drops below a few...
This circuit uses an integrated CMOS having the frequency determined by the resistors and...
The purpose of this circuit found in a 1995 magazine is to monitor an alarm via telephone. When we...