Free electronic circuit design and schematic diagram
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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It is fun to make a variable space in your small room, but it’s hard to make the actuator to move your wall or room partition. Using analog audio line delay, you can adjust your room virtually. Just turn a knob in your audio set and you can adjust your room size. The circuit described here will make your dream […]
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The first thing you must have in your workshop/lab is power supply. In experimenting many new electronic circuit design, it is easier if you have a flexible adjustable power supply. Here is an adjustable 0-30 volts power supply design. The circuit schematic diagram is shown below. The core of the circuit is 723 voltage regulator integrated circuit. A Darlington pair […]
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For anyone who love transistor circuits, here you can find small wattage discrete amplifier. Building discrete amplifier is much more fun and some people say it’s involve more artworks than building the ones with integrated circuit. Look at the figure below for the circuit’s schematic diagram. A variable resistor 470 Ohm is provided in series with two 1N4148 diodes to […]
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We can make a simple touch switch using only two inverter gates, two resistors, and two capacitors. The schematic diagram of the circuit is shown in the figure below. At power up, the output (of U1A) will be high, and the inverting output will be low because U1A gate will be triggered to ground level by C2. After triggered, the […]
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When you switch on your amplifier, you can see your speaker pop up with high power, and it can be harmful to your speaker. To make your speaker’s life time last longer, you have to avoid such situation. You can use an electronic circuit to protect your speaker, that connect your speaker to your power amplifier 1-2 second after the […]
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If you need +-15 Volts supply and you have only a standard 12V AC transformer, don’t be hurry to buy a new one with center tap, you can use your old transformer! The schematic diagram of this circuit is shown in the figure below. The voltage before entering the regulator IC 7815 and 7915 might reach 24 volts, if there […]
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