5V Low Drop Out Regulator Low Volt by BD438

The general regulator circuit, need input voltage is higher than the output voltage. So cannot apply to the input voltage is higher just little than the need voltage. But this circuit you can have the five volt output from input voltage only six volt of the normal battery.
5V Low Drop Out Regulator Low Volt
As circuit picture below. The load is connected with collector pin of the transistor output. Connection this way makes transistor works in a saturation. As a result the voltage drop across the collector pin and emitter pin very low (because to be the saturation voltage).
-And this current depends on a type of transistors, Which is set about 0.5 amperes, has a voltage drop is 0.2 volts. But for all circuit need plus with voltage across R6. (Current limiting resistor)
At voltage across R6 is about 0.5 volts. T3 is activated and the output current is limited there. LED-D1 is the second function is indicate working and the reference voltage. Which is set 1.5 volts to 1.6 volts at emitter pin of T1, for base current to drive it works.
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