Please tell me, USB=5V power supply to charge the rechargeable battery, the indicator light needs to be turned off when the battery is charged to 4.1V. Is the following circuit possible? If possible, what should be the value of the R1 and R2 resistors, and how to calculate it? In addition, Are there other simpler indicating circuits that can achieve this function?
Sabrina Posted on October 20, 2020
First determine the current of the LED light. Look at the tube amplification factor HEF IC≈IE IC=HEF*IB. IB determines R1, R2 should be able to be calculated.
Giselle Posted on October 20, 2020
Because the transistor's transmitting junction voltage is sensitive and the temperature coefficient is relatively large, the reliability of this circuit is not trustworthy.
Edgar Posted on October 20, 2020
This can refer to:
