Here is the circuit diagram of a battery eliminator circuit that can be used as a
replacement for 9V PP3 batteries. The circuit given here can be used to power any device
that operates from a 9V battery. The transformer T1 steps down the mains voltage and
bridge D1 performs the job of rectification. Capacitor C1 is a filter. IC LM317T is the
regulator here. The value of R1, R2 and R3 are so selected that the output voltage of
IC1 will be steady 9 volts.
Notes.
Assemble the circuit on a good quality PCB.
Transformer T1 can be a 230V primary, 9V secondary, 1.5A step down transformer.
If 1A Bridge is not available, then make one using four 1N 4007 diodes.
Do not connect loads that consume more than 1.5A to this circuit.
A heat sink is recommended for IC1.
source: http://www.circuitstoday.comreplacement for 9V PP3 batteries. The circuit given here can be used to power any device
that operates from a 9V battery. The transformer T1 steps down the mains voltage and
bridge D1 performs the job of rectification. Capacitor C1 is a filter. IC LM317T is the
regulator here. The value of R1, R2 and R3 are so selected that the output voltage of
IC1 will be steady 9 volts.
Notes.
Assemble the circuit on a good quality PCB.
Transformer T1 can be a 230V primary, 9V secondary, 1.5A step down transformer.
If 1A Bridge is not available, then make one using four 1N 4007 diodes.
Do not connect loads that consume more than 1.5A to this circuit.
A heat sink is recommended for IC1.
