The 220-240V AC mains source is stepped down to 9V AC by transformer X1. The transformer output is rectified by diodes D1 through D4 connected in bridge configuration and the positive DC source is straightly wired to the charger”s output contact, while the negative terminal is connected through current limiting resistor R2.
LED2 operates as being a power indicator with resistor R1 serving as the current limiter and LED3 signifies the charging status. While in the charging period, about 3 volts drop happens across resistor R2, which switches on LED3 through resistor R3.
yes, you can use center tap type of transformer. use only 9v and 0v for the circuit
Please let me know, can I use a 9-0-9V/250 mA Transformer in place of existing 0-9 V/250 mA ?