The wide voltage constant current timing charger circuit fabricated by MC14541 is mainly composed of power supply circuit, timing control circuit, control drive circuit, charging circuit and indicating circuit. 
The power circuit consists of AC220V power supply, transformer T, rectifier diodes VD2~VD5, filter capacitors C1 and α, current limiting resistors Rl and R2, and voltage regulator diode VDl.
The timing control circuit is composed of resistors R3 and R4, adjustable potentiometer RP, capacitor C3, and MC14541.
The control driving circuit is composed of a resistor R5 and a driving transistor VT.
The charging circuit is composed of LM317 type three-terminal voltage regulator integrated circuit A2, resistors R6~RlO, diodes VD6 and VD7. The LM317 type three-terminal voltage regulator integrated circuit A2 is the core of the charging circuit. Its 3 pin is the input terminal Uin of the power supply voltage, the 2 pin is the output terminal Uout of the charging voltage, and the 1 pin is the adjustable terminal ADJ of the output voltage. As long as the 3 pin is added to the voltage, the 2 pin has a voltage output, and the voltage between the 2 pin and the 1 pin is always clamped at 1.25V and constant, and the pin 2 controls the voltage high/low of the 2 pin. When the voltage of pin 1 rises, the voltage of pin 2 also rises; when the voltage of pin 1 decreases, the voltage of pin 2 also decreases.
The indicating circuit is composed of the light indicating diodes LED1 and LED2.
The power source G is a charged battery.
The above is part of the description information, working principle and more content can be found in the PDF document!
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