NiMH Battery Charger Circuit

Nickel Metal Hydride battery that demands present regulated charging. The charger offers 140 mA current for quick charging of the battery.Power provide part consists of a 0-18 volt AC one Ampere step-down transformer, a full wave bridge rectifier comprising D1 through D4 along with the smoothing capacitor C1. Current regulation is accomplished from the action of R1,R2 as well as the Epitaxial Darlington PNP transistor Tip 127. Resistor R1 retains the charging current to 140 milli amperes. LED and resistor R2 plays an significant role to manage the base current of T1 and therefore its output. Around 2.6 volts drop develops across the LED which seems in the base of T1. Emitter - base junction of T1 drops about 1.two volts. So two.6 - 1.2 volts offers 1.40 volts. Therefore the current passing by means of R1 are going to be 1.40 V / ten = 0.14 Amps or 140 Milli Amps. The LED act because the charging status indicator. LED lights only when the battery is connected to the output of circuit and the input voltage is regular.

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