## Simple Transistor Tester Using 555 IC

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 …[Read More]

## Frequency To Voltage Converter: Change Your Voltmeter To Frequency Meter

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 …[Read More]

Bulk Transistor Tester – An Easy Transistor Gain Classifier

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 …[Read More]

Capacitance Meter Using 555 Oscillator

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 …[Read More]

Single Input to Differential Input Adapter for Digital Voltmeter

I some cases, a differential input is needed for voltage measurement. Using the only one operational amplifier, you can build an adapter to provide a floating input for your ground-referenced  voltmeter. Use 1% tolerance metal film resistor for R1 and R2.  Adjust VR1 to give zero voltage output when the input probe is shorted.  You …[Read More]

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