Hi,
I have a very basic question. I appreciate any help. I know a *little* about DC circuits, and I have done some research online, and I will admit that I do not completely understand the calculations required.
I have a device that I am adding several LED lights to. The device runs on 2 AA batteries, but the 3v is stepped down to 2 volts, so effectively the circuit is running at 2v. I am not sure of the current, because my volt meter doesn't gave an ma ratting for it. I assume it is above 200ma, though that seems high to me.
Now my LED's run between 2.2 and 3.7 volts. Yes, blue is real power hungry. current for the LED's range from 10 to 36ma. Total current ratings for all LED's is roughly 190 ma.
I tried this...
Bought a transistor. TIP31 seemed the best fit from Radio Shack's collection (Which is limited). http://www.radioshack.com/product/i...oduct+Type/Transistor&fbc=1&parentPage=family
I ran a connection straight from the batteries into the collector (3v), put an LED on the emitter, and ran it to the negative lead. I ran a connection from the 2v output into the base, as this 2v is only available when the device is turned on. Seems to me, when the device turns on, the 2v current should close the transistor, and I should get right around 3volts out, but instead I get 1.6 volts out, at right around 200ma. ??????? why?
So i am looking into an IC chip to step up the voltage. Found a number of diagrams, no clue how to do the math, but I'll work on that later. Right now i jsut want a prototype to prove the theory that what I am doing is possible. I know that using an IC is the proper way to handel this, and to me, will be much more fun to play with.
I also know that I can use a capacitor and a diode (i think) to store the charge and release the current all at once, cycling very quickly, to power the LED's appropriately. I researched capacitors, farads, and coulombs, and all that good stuff, and I really don't understand how this relates to what current in will result in what current out the other side.
What capacitor should I use for this?
Should I use one to put out enough power for the 3.7v LED, and use resistors for the rest?
would it be better to use a capacitor that is closer to the current rating for each color LED, and run the capacitors in parallel?
I am running the LED's in parallel.
Please help. My brain hurts.
I have a very basic question. I appreciate any help. I know a *little* about DC circuits, and I have done some research online, and I will admit that I do not completely understand the calculations required.
I have a device that I am adding several LED lights to. The device runs on 2 AA batteries, but the 3v is stepped down to 2 volts, so effectively the circuit is running at 2v. I am not sure of the current, because my volt meter doesn't gave an ma ratting for it. I assume it is above 200ma, though that seems high to me.
Now my LED's run between 2.2 and 3.7 volts. Yes, blue is real power hungry. current for the LED's range from 10 to 36ma. Total current ratings for all LED's is roughly 190 ma.
I tried this...
Bought a transistor. TIP31 seemed the best fit from Radio Shack's collection (Which is limited). http://www.radioshack.com/product/i...oduct+Type/Transistor&fbc=1&parentPage=family
I ran a connection straight from the batteries into the collector (3v), put an LED on the emitter, and ran it to the negative lead. I ran a connection from the 2v output into the base, as this 2v is only available when the device is turned on. Seems to me, when the device turns on, the 2v current should close the transistor, and I should get right around 3volts out, but instead I get 1.6 volts out, at right around 200ma. ??????? why?
So i am looking into an IC chip to step up the voltage. Found a number of diagrams, no clue how to do the math, but I'll work on that later. Right now i jsut want a prototype to prove the theory that what I am doing is possible. I know that using an IC is the proper way to handel this, and to me, will be much more fun to play with.
I also know that I can use a capacitor and a diode (i think) to store the charge and release the current all at once, cycling very quickly, to power the LED's appropriately. I researched capacitors, farads, and coulombs, and all that good stuff, and I really don't understand how this relates to what current in will result in what current out the other side.
What capacitor should I use for this?
Should I use one to put out enough power for the 3.7v LED, and use resistors for the rest?
would it be better to use a capacitor that is closer to the current rating for each color LED, and run the capacitors in parallel?
I am running the LED's in parallel.
Please help. My brain hurts.