Free electronic circuit design and schematic diagram
If you have a digital voltmeter, or any voltmeter with millivolt resolution and high input impedance, then you can use this temperature-to-voltage adapter circuit to measure room temperature. Here is the circuit’s schematic diagram: Note that the voltage output of this circuit is floating, not referenced to ground. You have to use separate supply if your voltmeter has single ended […]
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Current handling capability of a power supply system often needed to be checked. Finding high power rated variable resistor to provide variable load testing might be difficult. There is wire wound type but it’s not always available at your local store, and the price and performance might be disappointing. This variable high power “resistor” uses 2N3055 power transistor to provide […]
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Many analog ohm meters have non linear scale, so the resolution become worse at higher resistance value. This because they use cheap current source, only a series resistance to approximate an ideal current source. An ideal current source will force a consistent current amount regardless of the tested resistor value. Using regulated current source, the current flowing through the tested […]
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Testing whether a transistor is shorted or open usually done by ohm meter. You test if the base to emitter or collector permit a current flow in one direction. Here is the circuit’s schematic diagram: The 555 timer ( IC1 ) operate as a 12hz oscillator. The output of this oscillator (pin 3) drives the 4027 flip-flop (IC2). Clocked by […]
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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, change the input signal to a square […]
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This transistor tester is very helpful if you need to sort bulk transistors. In some market, if you know where to find it, sometimes you can get transistors sold in kg unit, not in single peaces unit. You can buy 1 kg of transistors with really cheap prices. Don’t be too happy right now because you have to be careful, […]
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The frequency formula of 555 oscillator is popularly known. For a known resistors and capacitor, the frequency can be determined by a formula. From the math logic, if the frequency and the resistors are known, then an unknown capacitor could be determined by the inverse of the formula. Anyone who has a frequency counter are able to use the following […]
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