By this circuit you can run more than 70 LEDs by an AA battery.
The circuit draw 100 to 200 mA from the battery. you can find the choke coil from a mobile charger or old flash camera or rechargeable fly zapper.
Parts list:
Transistor 2N2222
Resistor 1k
Chock coil
LED(70pcs)
Battery 1.5v
NOTE:
1-test the output voltage before connecting that to the parallel LEDs. (2-3v is good)
2-using bigger transformer(choke coil) and power transistor maybe raise the output voltage up to 100v.
