102450 battery.Automatic nickel-cadmium battery charging circuit

China Battery Network currently sells chargers on the market. After the battery is fully charged, some cannot cut off the charging DC path. Although some can cut off the DC path or automatically switch to trickle charging, they cannot cut off the high-voltage AC path. If you forget to remove the battery in time and keep the power on for a long time, the following situations will occur: Chargers currently sold on the market. After the battery is fully charged, some cannot cut off the charging DC path. Although some can cut off the DC path or automatically switch to trickle charging, they cannot cut off the high-voltage AC path. If you forget to remove the battery in time and keep the power on for a long time, the following will happen:

Chargers currently on the market. After the battery is fully charged, some cannot cut off the charging DC path. Although some can cut off the DC path or automatically switch to trickle charging, they cannot cut off the high-voltage AC path. If you forget to remove the battery in time and leave the power on for a long time, the following hidden dangers will occur: first, power consumption; second, the power transformer will be powered on for a long time. It is easy to heat and burn; third, the battery is damaged due to overcharging. In response to this situation, this article introduces a charger that works well after long-term use. The circuit is shown in the figure. IC2 (CD4060) is a 14-bit binary serial counter/frequency divider, which controls the charging time together with VT1, K, etc. C4 and R4 are the reset and clear circuit of IC2. IC3 is a 555 integrated block. It forms an oscillator with a small duty cycle, and forms a pulse constant current charge and discharge circuit with VT2, VT3, VT4, etc. This circuit can charge the battery with large current to shorten the time. Charging time, and can eliminate the "memory effect" of the battery. Changing RIO and Rll can change the size of the charge and discharge current. LED2 controls VT2 and VT3 for constant current charging and also serves as charging indication. Adjust R7 and R8 to make LED2 light up for 100 seconds and off for 4 seconds. During the 4 seconds when LED2 is off and charging is stopped, tLED3 lights up for 1 to 2 seconds and fades out. At this time, the battery is discharged through VT4 and RII, and LED3 is used as a discharge indicator. Let’s discuss the charging and discharging current waveforms of the automatic nickel-cadmium battery charging circuit. Since the charging current can reach 150mA, appropriate heat sinks should be added to IC1 and VT3. The AA battery should be charged for 5 hours. Adjust R2 to make LED1 turn on and off at intervals of 18 seconds. Pin 3 of IC2 outputs high level, VTI is saturated and conducts, and K pulls in to cut off the AC circuit. LED1 is the timer work indicator and power indicator. K needs to use a self-locking key switch with a relay, or a small relay, but the circuit needs to be slightly modified to ensure that the relay can self-lock during the power generation process. VD2 provides a discharge path for C6. When using, put in 2 to 8 batteries, press K, LED3 will light up for 1 or 2 seconds (the battery is discharged first), LED2 will light up after 4 seconds (charging starts), and LED] will light up after 18 seconds (the timer is working). In this way, the three indicator lights keep on and off according to their respective frequencies, which means that the charger is working normally.