Need help figuring out a resistor value

[idbl_Fanatic]

Ok, so I have something that runs off of 5 Volts, that I want to use in the car, what value should I use? I was thinking 70 Ohm. But not sure

[Charles U Farley]

what are you doing? is this replacing another resistor? are you making something? how many amps are you/do you want to draw?

[idbl_Fanatic]

Originally posted by vanillathunder
what are you doing? is this replacing another resistor? are you making something? how many amps are you/do you want to draw?

I am adding a volt meter, and it needs 5 Volts to turn on, instead or 12, no clue on the amps, but I am sure it's not much

[Charles U Farley]

whats the specs on the volt meter (i.e. internal resistance). im trying to think of what your doing looks like on paper.

[idbl_Fanatic]

http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWN:IT

[TITANIUM]

What color are the bands on the resistor?

[Charles U Farley]

ok, im a tard,

got to thinking, the voltmeter will have a high internal resistance, i.e. megaohms, and is otherwise irrelevent. whats the specs on what you want it to measure?

[idbl_Fanatic]

Originally posted by vanillathunder
ok, im a tard,

got to thinking, the voltmeter will have a high internal resistance, i.e. megaohms, and is otherwise irrelevent. whats the specs on what you want it to measure?

I am going to put that on the + and - wire at the amps, so that I can monitor the voltage drop as I compete, my amps have a tendancy to catch fire under 10.5 Volts

[Charles U Farley]

ok, hope this is what you wanted.

[idbl_Fanatic]

[x6369x]

Dood, go to Radio Shack and get a variable resistance pot (potentiometer). Wire it up, then adjust it till it reads 5 volts. Then measure the resistance.

[idbl_Fanatic]

Originally posted by x6369x
Dood, go to Radio Shack and get a variable resistance pot (potentiometer). Wire it up, then adjust it till it reads 5 volts. Then measure the resistance.

That's too easy

[Charles U Farley]

yeah,
for some reason, i earlier thought that you wanted to incorporate this as part of your amp, in the same circuit. take that drawing i gave you and instead of the second resistor, put in a 5v zener diode.

http://hyperphysics.phy-astr.gsu.edu...enereg.html#c1

this page should tell you everything you need

[DemoN]

Rick...you just get one instead of four?

you have a distribution block? you going to put it on the "IN" side or what?

i'm going to order some, but i didn't know if i should put a voltage meter on each amp or just at the dist. block. so i'm wondering how you were going to wire yours up.

wait...you have all your amps synced right? so they're all daisy chaining off each other.

[idbl_Fanatic]

Originally posted by DemoN
Rick...you just get one instead of four?

you have a distribution block? you going to put it on the "IN" side or what?

i'm going to order some, but i didn't know if i should put a voltage meter on each amp or just at the dist. block. so i'm wondering how you were going to wire yours up.

wait...you have all your amps synced right? so they're all daisy chaining off each other.

Not anymore, they are different amps now, I am just wiring it in to the distro block, so I can see what the drop is there, I also put a suction cup on the back of it, so that I can take and stick it to the window on the outside when I am competing.

Oh yeah, and a 100 Ohm resistor worked just fine!

Here are some pics.

[DemoN]

got a pic of it working yet?

BTW: thanks...you told me exactly what i wanted to hear :LOL:

hey...that's the 0-20V right?

[idbl_Fanatic]

Originally posted by DemoN
got a pic of it working yet?



hey...that's the 0-20V right?

I do now...........here they are, and yes it was the 0-20volt one

it is only at 14.02 Volts, cause the lights were on, and the 12.64 and .65 were with the engine off

[TITANIUM]

Cool!!!! You should do a write up on it in the Tech forum.

[x6369x]

Originally posted by idbl_Fanatic

MAN that engine compartment is dirty. Good think you compete in SPL and not IASCA SQ. :kidding: