Free Circuit Diagram

This sine wave generator is adjustable between 15 Hz to 150 kHz. The circuit is basically a Wien-bridge oscillator, with multiple capacitor selection. Here is the schematic diagram: A stereo 10k potentiometer is used to control the frequency. The dashed line connecting these two potentiometers show that both potentiometer has single axis.

Metal Detector Circuit Topology One of the simplest method of metal detecting is by beat frequency oscillator. Basically, the circuit consist of two balanced oscillator. One oscillator provides the reference signal, and other oscillator is acting as the detector element. The reference oscillator’s frequency is fix, while the detector oscillator is variable depending on [...]

This circuit provide automatic current limiting up to 8.4A. Unlike current limiter that uses only a resistor, this current limiting circuit doesn’t drop the voltage, or at least keep the voltage drop at minimum, until a certain current amount is exceeded. This current amount limit is adjustable from 1.4 A to 8.4A using a [...]

A PLL system can be used to build a frequency-selective frequency multiplier by inserting a frequency divider inside the feedback path between the VCO output and the phase error detector input. Here is the schematic diagram of a low-frequency synthesizer with a programmable three decades divider circuit. The frequency-divider modulus N can vary [...]

If you are a hobbyist or a professional electronic engineer who make many electronic e]experiment, troubleshooting, or testing, providing wide range variable voltage power supply in your lab or workshop will make your life easier. You can build your variable power supply using linear adjustable regulator, but switching technology let you design a very wide [...]

Frequency meter can be used in speed sensor, tachometer, or any measurement of repetitive signals. This frequency to voltage converter (FVC) can be used to turn your analog or digital voltmeter into a tachometer. The circuit’s schematic diagram is shown below. The circuit consist of three blocks. The first block is a squarer, [...]