Author Options:

Will switching the 100k resistor for a 1meg resistor in the following schematic kill my battery life? Answered

Here is the schematic: http://forum.hackedgadgets.com/viewtopic.php?t=114

I switched out the 100k resistor for a higher value resistor in order to make the photocell much more sensitive. 1meg was the first resistor that would keep my LED off in dim light. (I want the LED to power on only when it's "lights out." Will this kill my 9 volt battery? Is there a better method to make the photocell more sensitive?


The forums are retiring in 2021 and are now closed for new topics and comments.

Best Answer 12 years ago

Not at all. It will actually reduce the current drawn by the circuit by a factor of 10. The only risk is that the LED may not come on fully. If that's a problem change the transistor for a higher gain one e.g. BC547C, BC549C, BC550C, BC546, 2N5551.