Liquid level detector

The computer needs at least 180 millivolts peak-to-peak and the condenser microphone in my headset produces about 20 millivolts peak-to-peak into a 2.2k load with normal speech levels. There are USB ports on the machines, so I can use...

Here is an interesting circuit for a magnetic proximity switch which can be used in various applications. The magnetic proximity switch circuit, in principle, consists of a reed switch at its heart. When a magnet is brought in the...

The following circuit illustrates a Mini Audio Mixer with Level Control Circuits. Features include switchable high/low sensitivity, providing high performance. The Mini Audio Mixer circuit is designed to facilitate the mixing of multiple audio signals while allowing for level control...

An NE602 functions as a heterodyne detector, while Q1 serves as a sense oscillator. When L1 is brought near metal, it induces a change in inductance, resulting in a shift in the resonant frequency of L1 and C6/C7. L1...

This circuit serves as an alternative to the infrared (IR) beam break detector featured in the June 2009 issue of Silicon Chip. It utilizes a standard IR receiver IC, such as the Jaycar ZD-1942, to minimize sensitivity to ambient...

One of the simplest methods of metal detection is through a beat frequency oscillator. The circuit consists of two balanced oscillators: one provides a reference signal, while the other acts as the detector element. The frequency of the reference...