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?ViewItem&rd=1&item=3830537523&ssPageName=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 :devil:


http://www.vectorcom.net/eBay/Images/digital-panel-meter-3.jpg

[Charles U Farley]

ok, hope this is what you wanted.

[idbl_Fanatic]

http://img.photobucket.com/albums/v238/idbl_fanatic/digital-panel-meter-3.jpg

[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/hbase/electronic/zenereg.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.:D

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.:D

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.

http://img.photobucket.com/albums/v238/idbl_fanatic/100_1773.jpg

http://img.photobucket.com/albums/v238/idbl_fanatic/100_1772.jpg

[DemoN]

got a pic of it working yet? :D

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? :D



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

http://img.photobucket.com/albums/v238/idbl_fanatic/100_1777.jpg

http://img.photobucket.com/albums/v238/idbl_fanatic/100_1775.jpg

http://img.photobucket.com/albums/v238/idbl_fanatic/100_1774.jpg

[TITANIUM]

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

[x6369x]

Originally posted by idbl_Fanatic
http://img.photobucket.com/albums/v238/idbl_fanatic/100_1775.jpg
MAN that engine compartment is dirty. Good think you compete in SPL and not IASCA SQ. :kidding: