Free electronic circuit design and schematic diagram
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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Many cheap battery chargers usually assume that charging the battery slowly is OK although the battery is already full of charges. All they do is usually charging the battery with constant current no matter if the battery is almost completely discharged or has been fully charged. Off course the battery wouldn’t be damaged immediately after few charging cycles, but actually […]
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You can use a humidity sensor to give an alert of boat leakage, or when your books start being flooded by heavy rain attack on your broken roof, or anything you can imagine. A simple humidity sensor (a humidity probe) can be constructed using two copper wires placed as close as possible to each other, but no touching. This simple […]
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