I test a small alarm for current leakage with the switch in the OFF position.
Runs on 4.5 volt D.C.
It showed a drain of 2 uA.
Is that typical ?
Thanks,
Andy
more details please
"small alarm" = __________________________
model numbers are nice - description helps
Intermatic SP440B
I am using 3 AA batteries instead of expensive button cells.
Andy
in that case, 2uA sounds ok
that is a very small amount of current, really
although, if i had designed it, it would be pica-amps - lol
You have a meter that can detect that ?
One million millionth (10-12) of an ampere
no - but it can be calculated by measuring voltage drop across a series resistance
many CMOS circuits draw pico-amps or nano-amps when idle
in fact, many projects i've built use a 9V battery
in the idle state, so little current is drawn that i don't bother using an on-off switch
the 9V battery will last nearly as long as if it were sitting on the shelf
I was told that caps may be sucking some current.
The caps are not labeled, so I suspect they are bottom of the barrel stuff. :-)
http://i1289.photobucket.com/albums/b516/drew77580/Alarm2_zpsb07c41ef.png
http://i1289.photobucket.com/albums/b516/drew77580/Alarm1_zps4b8db9fa.png
I saw a procedure for determining the Farads, but it looked rather involved.
Andy
2 uA is a small amount of current
i doubt the capacitors are leaking
Alkaline AA batteries rated at something like 2000mAh should be able to sustain a 2uA current for far longer than the shelf life of the batteries.