# Mains Failure Alarm

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This circuit was designed to produce an audible alarm when the mains power is interrupted. Such an alarm is essential for anyone whose livelihood depends on keeping perishable foodstuffs in cold storage. The circuit is powered by a 12-V mains adapter. LED D5 will light when the mains voltage is… Read more »

# Circuit Project: Solar Panel Voltage Regulator

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Our energy-hungry and environmentally aware society has been slow to make good use of the sun’s “free” power. But now it’s finally taking off. Using the sun’s heat directly, for cooking and other applications, is already a common and popular technology in countries that have good weather. Hot-water panels are… Read more »

# LM78S40 5V to 15V Step-up Voltage Regulator

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We can do a step-up conversion without using transformer. Using this circuit, a 5V DC source can be converted into 15V. Please note that there is no power gain here, as we cannot create energy from nothing, it means that we can leverage the voltage but the current will drop…. Read more »

# Switchable 6V, 9V, and 12V Linear Voltage Regulator

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We can build a multiple voltage power supply 6, 9, and 12V  (AC-DC Adapter) with the circuit shown in the following schematic diagram.  Not only provide multiple voltage output with single voltage supply, this circuit add the benefit of regulating the voltage for better stability. A transformer with rectifier… Read more »

# Linear Power Supply Circuit

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A diode bridge, a step down transformer a linear regulator(U1) and some filtering capacitors can be used to build a Linear power supply. This circuit has some advantages such as this circuit has high output current and can give multiple output voltages easily. However it has some disadvantages like this… Read more »

# Low-Drop-Out (LDO) Low-Voltage Linear Regulator Using NCP2860 IC

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This low drop out (LDO) voltage regulator need only few components, with very low noise and very low drop-out voltage. The circuit illustrated in the schematic diagram below gives a fixed 2.77 volt output, but this output voltage can be adjusted using two additional resistors. This circuit capable to supply… Read more »

# High Efficiency Switch Mode 3.3A 10A Regulator

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This switch mode regulator circuit has higher current output than  our previous switch mode regulator, but it uses same controller IC. Up to 10A can be served by this switch mode regulator. The output of this regulator circuit is regulated at 3.3 volt, and the input range is 4-9Volt. The… Read more »

# High Efficiency Switch Mode 3.3V 5A Step-Down Converter

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This switch mode step-down converter has very good efficiency, up to 94% can be obtained. This switch mode regulator uses LTC1266-3.3 controller with external N-Channel power mosfet, and need only a 5uH inductor because it uses high frequency switching. Here is the schematic diagram of this switch mode step down… Read more »

# Transformerless, Switch Mode Boost Regulator, A Step-Up Converter

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Using this switch mode regulator circuit, you can get a stable 12 volt output (500mA) although you just have 4,3 – 10V power supply. You can even boost a 3.5V input to 12V if the load draws only 100 mA or less. This switch mode voltage regulator use LTC1266 IC… Read more »

# Transformerless Voltage Booster Circuit: A DC-DC Step-Up Switching Regulator Using Transistors

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A DC-to-DC step-up converter is traditionally implemented using transformer, working by converting the DC voltage to AC Voltage, step-up it using transformer, then rectify and filter the transformer’s output to  get a higher DC voltage. Using a switching method, we can step-up a voltage without a transformer. We just need… Read more »