a memo
Testbench results using prototypical parts.
Unit 1 consits of four AA batteries in series with a 1000 ohm resistor and a bright white LED. Total voltage is 4.8V, current in the circuit is 2mA. The NiMH batteries are rated at 1600mAH, will the LED stay lit for 30 days?
Turned on at 23:00 on October 22, 2002.
Unit 2 consists of two AAA batteries in series with a 460 ohm resistor and a bright white LED. Total voltage is 3.2V current in the circuit is a whopping 0.8mA (can it be???). The Radio Shack Enercell Plus batteries are unrated. How long will the LED stay lit?
Turned on at 23:00 on October 25, 2002.
Notes:
Unit 2 is slightly less bright than Unit 1, but side by side they look matched. It's only when you look at the pattern on the wall that you can tell.
The LEDs are rated at 20mA with a 3.6V forward voltage, but the voltage drop across the LED in these circuits is 2.8V. Must test with higher current, maybe I'm missing a big performance gain.
By Psydeshow on October 26, 2002 at 12:09am