Coherence
Newly Enlightened
Here is an easy to do project:
Take out the electronics from a Brinkman LED light, was (still is?) available from WalMart for about $12. You get a 2 transistor circuit on a board about 1"x1" that functions as a voltage step up.
here is what I measure:
Volts....mA
0.0......0
1.0......10 <-LED begins glowing
1.5......23
3.0......110
Even at 1.5 volts, the light glows fairly brightly, try it by removing one of the batteries in the Brinkman and shorting + terminal to - terminal (in the battery compartment, not the battery itself!).
At 3 volts it is really bright (can't stare into it). Of course with the circuit exposed it does not have the tight lens focused beam, as a bonus.
Okay I'll do the battery math, got the battery data from data.energizer.com
usable lifetime(in hours) = battery capacity (in mAh) / discharge rate (in mA)
for alkaline batteries @ 1.5 volt
AAA= 1150/23 = 50 hours
AA = 2850/23 = 124 hours
C = 8350/23 = 363 hour
D = 18000/23 = 783 hours = 32 days
I know that these times are based on cells getting down to 0.7 volt, so they are overly optimistic as the circuit ceases to function below 1.0 volt. However, this does not seem to be a constant power type circuit, as the current draw reduces as voltage is reduced. In other words, it will get dimmer as the cell is used, but stretching out the life of the cell.
If you want to drive the circuit at 3 volts then you will use 2 cells about 5 times faster than the above run times, the price you pay for high brightness. For instance, a 123A lithium cell (3 volt) will last about 1300/110 = 12 hours.
Okay, here is what I want if anyone knows how to do this:
make a 2 AA light where you can switch between using the batteries in series (bright mode ~25 hours) and in parallel (long runtime, ~250 hours), with no chance of one cell discharging through another while in parallel.
Is there an easy way to do this?
also if I made any math/reasoning errors someone correct me...
Take out the electronics from a Brinkman LED light, was (still is?) available from WalMart for about $12. You get a 2 transistor circuit on a board about 1"x1" that functions as a voltage step up.
here is what I measure:
Volts....mA
0.0......0
1.0......10 <-LED begins glowing
1.5......23
3.0......110
Even at 1.5 volts, the light glows fairly brightly, try it by removing one of the batteries in the Brinkman and shorting + terminal to - terminal (in the battery compartment, not the battery itself!).
At 3 volts it is really bright (can't stare into it). Of course with the circuit exposed it does not have the tight lens focused beam, as a bonus.
Okay I'll do the battery math, got the battery data from data.energizer.com
usable lifetime(in hours) = battery capacity (in mAh) / discharge rate (in mA)
for alkaline batteries @ 1.5 volt
AAA= 1150/23 = 50 hours
AA = 2850/23 = 124 hours
C = 8350/23 = 363 hour
D = 18000/23 = 783 hours = 32 days
I know that these times are based on cells getting down to 0.7 volt, so they are overly optimistic as the circuit ceases to function below 1.0 volt. However, this does not seem to be a constant power type circuit, as the current draw reduces as voltage is reduced. In other words, it will get dimmer as the cell is used, but stretching out the life of the cell.
If you want to drive the circuit at 3 volts then you will use 2 cells about 5 times faster than the above run times, the price you pay for high brightness. For instance, a 123A lithium cell (3 volt) will last about 1300/110 = 12 hours.
Okay, here is what I want if anyone knows how to do this:
make a 2 AA light where you can switch between using the batteries in series (bright mode ~25 hours) and in parallel (long runtime, ~250 hours), with no chance of one cell discharging through another while in parallel.
Is there an easy way to do this?
also if I made any math/reasoning errors someone correct me...
