Free electronic circuit design and schematic diagram
Sawtooth wave oscillator is used in cathode ray tube deflection circuitry, in a PWM modulator, or in a analog to digital conversion. You can also use it in your own design, only your imagination can limit its application. Here is one example of the circuit: The frequency is determined by C1, R1, R2, R3, and R4. This frequency formula can […]
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PLL oscillator is used to get very stable frequency woth very low distortion of sine wave output. The stability is equal to crystal-based oscillator, and the low distortion level of the sine wave output is equal to LC based oscillator. The method of PLL control in PLL oscillator is done by adjusting the frequency of sine wave VCO (voltage controlled […]
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The DC to AC inverter circuit shown in the schematic here is very simple circuit since it produce square wave, but it’s enough to power many devices. Here is the schematic diagram of the inverter circuit: The MOSFET is configured as bridge, so the current will flow alternatively in through the primary windings of the transformer. The most expensive part […]
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Fluorescent lamp or tube lamp (TL) has good efficiency. This high efficiency feature make it suitable for battery operated lighting application. To drive the tube lamp, we need high voltage to make the gas inside the tube get ionized. Here is the schematic diagram of the fluorescent lamp circuit: To trigger the ionizing process, we need high voltage as high […]
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This inductance meter is actually an adapter to your digital voltmeter (DVM). Using this circuit now your voltmeter is capable of measuring inductor value. Inductance meter is very helpful in designing switch mode power supply, since its often needed to wind the coil by hand and measure the inductance fro trial and error to get the required value. Here is […]
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If you are a hobbyist or a professional electronic engineer who make many electronic 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 voltage adjustment range without loosing […]
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Capacitance meter can be very helpful in identifying old components where its mark has been erased or became unreadable. Such instrument can be quite expensive, but fortunately we can build it easily with much lower cost. The capacitance meter described here can measure any capacitor between 1pF and 10uF. Here is the schematic diagram of the circuit: You can just […]
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