Clever fuckers or electrical engineers. and shit.

[Akzle]

okay, so's i has an analog multimeter. on it it has 10v dc and 50vdc, the face is scaled also for .25ma and 250vac.

now, when doing auto/12vdc shit, 10a is too low, but 50 doesn't offer the resolution. so is there a clever cunt who can tell me what resistor i need in there to HALVE the 50v range so it's 25vdc, which will give me better resolution for 12-14vdc measurements.

thankyou in advance.

(i tried installing linux, but i mangled the USB when i RAMed it.)

[bogan]

Digital ones are like 20 bucks...

Failing that, what you need is a resistor the same as to your multimeter resistance. To figure that out you can put a multimeter on it to measere its resistance, cheap digital ones sell for around 20 bucks. Now you have the resistance, go back into the shop and buy another resistor of the same size, and put in series to make it work.

[Akzle]

Digital ones are like 20 bucks...

Failing that, what you need is a resistor the same as to your multimeter resistance. To figure that out you can put a multimeter on it to measere its resistance, cheap digital ones sell for around 20 bucks. Now you have the resistance, go back into the shop and buy another resistor of the same size, and put in series to make it work.

now why the fuck didn't i think of that.

i have 2 digital ones already, and i'll be getting a third sometime soon :soon:

i just like the analog with the dial thing as i can see at a glance if it's within range.

[Akzle]

a man with one watch knows the time. A man with 2 is never sure :facepalm:
next q.
Its measure 1.016MR
nearest resistors avail are 1R and 1R2. Methinks 1R2. Or whether i drill a pot in... For fine adjust.

[bogan]

a man with one watch knows the time. A man with 2 is never sure :facepalm:
next q.
Its measure 1.016MR
nearest resistors avail are 1R and 1R2. Methinks 1R2. Or whether i drill a pot in... For fine adjust.

Aren't 1R and 1R2 about 6 orders of magnitude off, may want to put them on the digital meter too just to check.

[Akzle]

That is measuring with the digi. The r on the board is .8 something, but goes round in circles and i womt trace it if i dnt hav to.
Buuuut... Thats the opposite, innit. I want half the resistance...
Also, it says right on it, 20kR/v.
Which means i want 0R5...

[Akzle]

my handy dandy chart tells me 510 is the nearest, but only avail 1/2watt.

[Akzle]

Adding in series doubl resistance, putting in parallel halves. So if i put another .8 in paralel with the one on the board i should be right. But makes it permanent. Switch needed.
Right?

[Smifffy]

Adding in series doubl resistance, putting in parallel halves. So if i put another .8 in paralel with the one on the board i should be right. But makes it permanent. Switch needed.
Right?

Don't go near any of that white man's magic. It will steal your soul.

[Akzle]

Don't go near any of that white man's magic. It will steal your soul.

will it measure it by 25v?

[yeahnahbe]

Thats gonna make 50v the new 25. Probably easiest to put a 1M in parallel than replace the 1M with a 500k. This introduces accuracy problems if you're testing a circuit with high impedance. If it's right off the battery terminals then all good.

[Akzle]

Thats gonna make 50v the new 25. Probably easiest to put a 1M in parallel than replace the 1M with a 500k. This introduces accuracy problems if you're testing a circuit with high impedance. If it's right off the battery terminals then all good.

i was thinking exactly that. But have the second one switched in, for if i ever want 50v res.
Thanks dude.

[paturoa]

Resistors are not very precise components particularly the cheap ones. Even the good ones are only +/- 5%.

[Smifffy]

Resistors are not very precise components particularly the cheap ones. Even the good ones are only +/- 5%.

Check out the 'occupy' thread! The inaccuracies from the resistors in there are off the chart!

[paturoa]

Check out the 'occupy' thread! The inaccuracies from the resistors in there are off the chart!

Do we still have the best post of the year competition? That is a nomination right there!

[Dave-]

Check out the 'occupy' thread! The inaccuracies from the resistors in there are off the chart!

2x for best post

Akzle there are online calculators that allow you to plug in any value for R and it'll spit out a circuit that has exactly that resistance (allowing for uncertainties)

[Akzle]

well fuck the lottaya.
Bogan, despite being 100% fucking wrong, you put me in the right direction, thx.

139kR. New banana chasis socket. Win. Handy dandy trim potentiomnomnomiter, got me the value i needed.
Increased r on 10v rather than trying to bring down 50.
Wil pix later.

[Akzle]

derp derp.

while trim pot meas 139. it should be a *calculated* 100kR. and it seems, that it should be, so i'm going to pull the cunt apart again, and swap out the 3 i put in, for one, at 100kR.

pics anyway:

[davereid]

[COLOR="#139922"]okay, so's i has an analog multimeter. on it it has 10v dc and 50vdc, the face is scaled also for .25ma and 250vac.

OK if you want to use the 10v range to measure voltages up to 20v just get two identical resistors. The value isnt really important, anywhere from 1k to 100k will do at a pinch, but I would suggest 10k.

Then put the resistors in SERIES.

Place the resistors across the voltage you wish to measure. Exactly 1/2 of the voltage will be evident across each resistor.

So measure across either resistor with your multimeter to get your result.

[Akzle]

OK if you want to use the 10v range to measure voltages up to 20v just get two identical resistors. The value isnt really important, anywhere from 1k to 100k will do at a pinch, but I would suggest 10k.

Then put the resistors in SERIES.

Place the resistors across the voltage you wish to measure. Exactly 1/2 of the voltage will be evident across each resistor.

So measure across either resistor with your multimeter to get your result.

yes. or. since i've done this already, i could just put the right resistance in so i've got a nifty 15v range banana socket.