LM317T Voltage Regulator with Pass Transistor

Adjustable Voltage Stabilizer An adjustable voltage stabilizer is an integral part of a modern radio electronic device. The voltage stabilizers most commonly used for this application are integrated voltage stabilizers - or integrated circuits. In most cases these are microchips designed for a standard fixed voltage value. However, some cases require voltage that is different from the standard one. Or we might need a power source with adjustable output voltage. Such power source can be assembled using a microchip - an adjustable voltage stabilizer, say, LM317. This microchip is offered be many producers and in different configurations, for various load currents, and, respectively, in a variety of cases - from SO-8 to ТО-3. The standard microchip connection circuit is very simple and requires just a small number of additional elements. The power unit consists of a step-down transformer, a diode bridge and evening capacities. An input capacitor needs to be connected to eliminate high-frequency generation in step-like connection of input voltage. The output capacitor provides stability in pulse changes of the load current and decreases the level of pulsation. The output voltage is adjusted using a variable resistor, which forms a bleeder together with the fixed resistor R1. By changing the resistance of a variable resistor we control the output voltage, according to the formula. 1.25 coefficient in this formula is the value of voltage reference. This device will help you ...



http://www.youtube.com/watch?v=ULDxSGGBz9A&hl=en