What is the total resistance of many test points?

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Say I have a box with unknown inside. I'm asked to figure out the total resistance by only using these spikes with a multimeter/analog meter. How would I go about doing this?




spike box.jpg
 

mcgyvr

Joined Oct 15, 2009
5,394
Total would entail you measuring resistance across each pair of pins and summing all the readings of each of the pairs..
 

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Total would entail you measuring resistance across each pair of pins and summing all the readings of each of the pairs..
So would I write a chart? As in pin 1 to pin 2, pin 1 to pin 3 and so on. And add up the readings? Or simply find the highest value?
 

ErnieM

Joined Apr 24, 2011
8,377
You show 16 pins and do not define what "total" means.

To determine pin to pin resistance measure between pin 1 and the remaining 15 pins. 15 measurements total.

Then repeat for pin to to the remaining 14 pins (you already have pin 1 to 2). Repeat for the remaining 14 pins.

And so on until you finish by reading pin 15 to pin 16.

Next, reverse the probes and do it again unless you are certain your unknown contains only pure resistances and no diode elements.

That is either 120 or 240 measurements, and what you do with them is entirely up to you.
 

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Thank you. You wouldn't happen to know where I could find a circuit diagram connected to pins such as these would you? I'd like to see an example
 

ErnieM

Joined Apr 24, 2011
8,377
Your sketch seems to be of a connector. A connector is a general use item used to connect one thing to another.

Here "thing" is intended to convey almost anything can be connected to a connector.

Thus there are no examples to share.
 

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Your sketch seems to be of a connector. A connector is a general use item used to connect one thing to another.

Here "thing" is intended to convey almost anything can be connected to a connector.

Thus there are no examples to share.
I realize that. It's a small box with a battery inside. Do you know of any circuits such as this that are connected to this many pins?
 

mcgyvr

Joined Oct 15, 2009
5,394
Why do you ask which the highest is? Is that important?

I'm also not sure what you're saying in your last comment. Can you elaborate?
Ignore DZR... Seems they aren't aware of "forum etiquette".. And is just trying to get an answer to his problem with his welder in your post (commonly referred to as hijacking)
Or just isn't aware where he is even posting responses to.. (commonly referred to as being in la-la land :) )

back to your question..
I'm not sure what benefit you expect to achieve looking at other "circuits".. But there are THOUSANDS (millions) of circuits out there that connect to pins/connectors..
Looking at random circuits connected to pins isn't going to help you at all.. (whatever your goal is)..

So...What is your whole goal here?
Is this a class assignment?
Do you have a random box and you want to know what it does?
Did you find this in your front yard or something?

This forum is usually very helpful.. But we don't read minds and won't sit here and pull information from you..
Ask a question.. provide as much detail as you can.. be straight with us and welcome to the forum..

We have already answered your question about how to find the total resistance (given the information you have provided)..
Then as Ernie points out in post #9 just knowing the resistance of pins doesn't tell you a damn thing about what the device actually does... Its far more complicated than that..
 

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Ignore DZR... Seems they aren't aware of "forum etiquette".. And is just trying to get an answer to his problem with his welder in your post (commonly referred to as hijacking)
Or just isn't aware where he is even posting responses to.. (commonly referred to as being in la-la land :) )

back to your question..
I'm not sure what benefit you expect to achieve looking at other "circuits".. But there are THOUSANDS (millions) of circuits out there that connect to pins/connectors..
Looking at random circuits connected to pins isn't going to help you at all.. (whatever your goal is)..

So...What is your whole goal here?
Is this a class assignment?
Do you have a random box and you want to know what it does?
Did you find this in your front yard or something?

This forum is usually very helpful.. But we don't read minds and won't sit here and pull information from you..
Ask a question.. provide as much detail as you can.. be straight with us and welcome to the forum..

We have already answered your question about how to find the total resistance (given the information you have provided)..
Then as Ernie points out in post #9 just knowing the resistance of pins doesn't tell you a damn thing about what the device actually does... Its far more complicated than that..
It's a class project. My teacher wants to know what steps we would do to measure the resistance and voltage. I know the first step would be to turn the power off, then measure between each pin like said above. The voltage would be all the same if connected to one battery.
 

Thread Starter

cdynasty001

Joined Oct 17, 2016
8
Also, the admin blocked my other post saying this is the same question. It's an entirely different question man. Thanks for blocking my post.
 

ErnieM

Joined Apr 24, 2011
8,377
It's a class project. My teacher wants to know what steps we would do to measure the resistance and voltage. I know the first step would be to turn the power off, then measure between each pin like said above. The voltage would be all the same if connected to one battery.
Once you put a battery inside the box each and every pin to any other pin may show a different voltage.
 

mcgyvr

Joined Oct 15, 2009
5,394
Also, the admin blocked my other post saying this is the same question. It's an entirely different question man. Thanks for blocking my post.
So... whats your new question?
Other than "how do I pay more attention in class so I know the answers to the questions asked by the teacher?" :p
 

WBahn

Joined Mar 31, 2012
30,055
Total would entail you measuring resistance across each pair of pins and summing all the readings of each of the pairs..
We know that won't work.

Consider if there was a single resistor in there in which half of the pins were connected to one side and the other half were connected to the other. This approach would yield a value that is 64x the value of that resistor.

Without knowledge of the possible circuit topologies that might exist in the box you can't divine very much information about what's in there at all. Add a battery to the mix and all bets are off.

The very notion of what "total resistance" means in this context is completely undefined.
 

mcgyvr

Joined Oct 15, 2009
5,394
We know that won't work.

Consider if there was a single resistor in there in which half of the pins were connected to one side and the other half were connected to the other. This approach would yield a value that is 64x the value of that resistor.

Without knowledge of the possible circuit topologies that might exist in the box you can't divine very much information about what's in there at all. Add a battery to the mix and all bets are off.

The very notion of what "total resistance" means in this context is completely undefined.
It would work if the definition of "total resistance" means to ............ measuring resistance across each pair of pins and summing all the readings of each of the pairs.. :)
But as many of us have stated.. "total" is underfined (and the assignment is a wild goose chase/waste of time anyways... as described to us)
 

WBahn

Joined Mar 31, 2012
30,055
It would work if the definition of "total resistance" means to ............ measuring resistance across each pair of pins and summing all the readings of each of the pairs.. :)
But as many of us have stated.. "total" is underfined (and the assignment is a wild goose chase/waste of time anyways... as described to us)
So the "total" needs to be penalized more? :D
 
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