Tag Archives: regulator

9 Volt 2 Ampere DC Power Supply Circuit Diagram

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A simple 9 Volt 2 amp supply using a single IC regulator. There is little to be said about this circuit. All the work is done by the regulator. The 7809 can deliver up to 2 amps continuous output whilst maintaining a low noise and very well regulated supply. The… Read more »

Power Supply For USB Devices

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More and more equipment is sold that runs off internal rechargeable batteries. Although a matching charger is usually supplied in the package, there are also devices that can only be charged via a USB port. That is not surprising in the case of USB MP3 players, which have to ‘dock’… 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 »

Dual Regulator Handles Two Input Voltages

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The circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regulator accepts either 3.3 or 5V inputs, you could plug it into either a new 3.3V system or an old 5V system.The circuit consists… Read more »

High Input Voltage Linear Regulator

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Commonly used 3-pin linear voltage regulators, for example the LM317, cannot handle input voltages in excess of about 30V. The LR8A from Supertex Inc is a new, adjustable three pin regulator that can accept input voltages up to 450V and can supply an output current of 0.5mA to 10mA. Using… Read more »

Low-Drop 5V Regulator

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A 4-cell pack is a convenient, popular battery size. Alkaline manganese batteries are sold in retail stores in packs of four, which usually provide sufficient energy to keep battery replacement frequency at a reasonable level. Generating 5 V from four batteries is, however, a bit tricky. A fresh set of… Read more »

High Current Low-Dropout Voltage Regulator

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This circuit was designed to allow a laptop computer to be powered from a solar power setup. The computer requires 12V at 3.3A. The circuit is a linear regulator with Mosfet Q4 as the series pass device. A 100kO resistor provides Q4 with a positive gate-source voltage. Any tendency for… Read more »

RS232 Voltage Regulator

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There are many small applications where it would be preferable to power a device directly from an RS232 (V.24) interface, avoiding a mains power supply. Most ICs require 5 V, and the interface can provide a current of around 8 mA, almost all of which would be consumed by a… Read more »

Thrifty Voltage Regulator

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One of the drawbacks of a three-pin voltage regulator is that the input voltage needs to be 2.5–3 V higher than the output voltage. This makes these integrated regulators unsuitable for battery power supplies. If, for instance, the output voltage is 5 V, a 9 V battery could be discharged… Read more »