Re: LEDs – Expanding Batteries – CR2032 to 2 C or D size

Home Evil Mad Scientist Forums Ask an Evil Mad Scientist LEDs – Expanding Batteries – CR2032 to 2 C or D size Re: LEDs – Expanding Batteries – CR2032 to 2 C or D size

#21804
MarlyManning
Participant

WOW!  8,000 hours would be great!  Many thanks!  Sorry I am really new at this.  So long as I don’t change the voltage, do I need additional resistors or can I just simply use:

(2)  C or D batteries in series => ~
3.0 volts    to replace one   CR2032 => ~ 3.0 volts, 3 mA
(3)  C or D batteries in series => ~
4.5 volts    to replace one   LR44 => ~ 4.5 volts

1)  Without additional resistors?  Or, 2)  Do I need to measure the current on the existing circuit (A1) with a multimeter and then protect the LED by using the formula V = I x R, for the first example 3.0 = A1 * R1

Many thanks!!!