ok electronic engineers, heres a ?? for you

[kimcrwbr1]

You could also get a 120 volt inverter and then buy a charger to step it down to your specs that way you have the 120 volt capability ta boot? Plug and play.

 

[cammeddrz]

i have given up on the battery thing.

NEW QUESTION:
i need to power a few l.e.d.s that have ab operating voltage of 3.5V, and 4.0V max. and a current of 20ma

WHAT DO I NEED TO BUY FROM THE THE 'SHACK FOR THIS? i imagine this to be much easier

 

[bobbywalter]

i would probably just use a zener

 

[gwaii]

i have given up on the battery thing.

NEW QUESTION:
i need to power a few l.e.d.s that have ab operating voltage of 3.5V, and 4.0V max. and a current of 20ma

WHAT DO I NEED TO BUY FROM THE THE 'SHACK FOR THIS? i imagine this to be much easier

voltage regulator-it's a simple three pronged i.c.

that or just a resistor.

 

[bobbywalter]

i used a zener for throttle control on the iac with a rotory pot. pretty rough way to go and turned the cel on as i bypassed the pcm with it and usually had to restart and set it.

worked

or maybe it was a resistor? pretty sure it was a zener.

 

[cammeddrz]

what is a zener?

and gwaii the regulator seemed like the easy part, the tiny amperage seemed to be the harder part. would it burn it out being on a circuit that has hundreds of amps? or would it only draw what it wanted to draw?

 

[gwaii]

it would only draw what it needed.that's where the problem with the battery came in,it'll draw all it can...it act's like an open load.the leds can have as big a power source as you want connected to them,as long as the voltage is regulated(and in most applications it's simply done with a resistor)you'll be fine.

 

[gwaii]

what is a zener?

a zener is simply a voltage regulated diode.

if a diode can be thought of as a one-way valve for electricity,a zener can bee seen as a one way valve that has a pressure regulator built into it's blocked side.so it will block the voltage up to a certain voltage,then maintain this pressure(voltage)difference across the scale of voltages applied to it.
this is why they are usefull as a reference voltage device,and why i mentioned it's use in conjunction with a transistor to operate a negative feedback charger.