As an exercise for learning the above, breadboarding, and Ohms law, I built the below circuit and after a lot of false starts, smoke, and blown fuses, i eventually got the correct readings.
As an aside, does measuring current on parallel circuits give newbies trouble ? Especially where to put the probes, etc ?
Anyhow, after I got the correct readings at each resistor, I was trying to figure out how to get the current flow through any 2 adjacent resistors.
After a bunch of fumbling it seemed to me that if I simply removed the 3rd resistor entirely, then measured the total current, I would have my answer.
Somehow that seems too easy so did I do it properly ?

Well, the photo that I downloaded ends in .wep or somesuch so I can't download it.
I got it from the Kirchoff current lesson here.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-6/kirchhoffs-current-law-kcl/

Good exercises here.

Thanks
George

 

As an aside, does measuring current on parallel circuits give newbies trouble ? Especially where to put the probes, etc ?

As long as the meter shunt resistance isn't high enough to affect the circuit, it should be straightforward. I can't remember the last time I used a meter to measure current. I usually opt for measuring the voltage drop across a resistor and calculating current.

Regarding your picture format. You can cut and paste into the text entry box.

 

As an exercise for learning the above, breadboarding, and Ohms law, I built the below circuit and after a lot of false starts, smoke, and blown fuses, i eventually got the correct readings.
As an aside, does measuring current on parallel circuits give newbies trouble ? Especially where to put the probes, etc ?
Anyhow, after I got the correct readings at each resistor, I was trying to figure out how to get the current flow through any 2 adjacent resistors.
After a bunch of fumbling it seemed to me that if I simply removed the 3rd resistor entirely, then measured the total current, I would have my answer.
Somehow that seems too easy so did I do it properly ?

Well, the photo that I downloaded ends in .wep or somesuch so I can't download it.
I got it from the Kirchoff current lesson here.
https://www.allaboutcircuits.com/textbook/direct-current/chpt-6/kirchhoffs-current-law-kcl/

Good exercises here.

Thanks
George

Hi,

For the general parallel circuit you can not remove components and expect to get the same current, but when that circuit is driven by a single voltage source that is also in parallel with all elements and that voltage source is ideal, then you can.
In your case it looks like you can because the voltage source is in parallel to all elements and it is ideal.

More often the voltage source is not in parallel to all elements so you cant do that. You have to either measure the current or use Ohm's Law or some circuit analysis technique.

In a real circuit however the voltage source is not ideal (like a battery) and so when you remove components the voltage across all elements will increase and that means the current through that one element you leave in the circuit will get more current than it normally does. If it is a good voltage regulator then it may work ok, but you see you have to be careful when you can do this and when not.

 

If this is the parallel circuit you're talking about:

You can place an ammeter at any of the red circles, or on the other side of the resistors, and measure the current in that leg.

To measure total current, you can insert an ammeter between points 1&2 or 7&8.

You should note that the current direction used on AAC tutorials is electron current.

Unless you're trying to convince yourself that KCL works, there's really no need to use ammeters. Using Ohms Law, you can calculate the current in each resistor and this problem was designed to allow mental calculations; so you don't even need a calculator.

 

I have total confidence in KCL , but I wanted to prove to myself that I could figure out where to put the probes and that I had got the wiring correct.
I had to watch a few videos to finally get it correct and I still have to stare at a breadboard for a while before placing the probes. I need the practice.
I was able to accurately measure the current on each leg.
I was also trying to figure out the total current through 2 legs. That I did by removing the 3rd leg.
And yes, that is close to the schematic that i used though mine was the same one but showed the current as
I1+I2+I3. I tried to figure out how to measure the current through legs 2 & 3.
I hope that makes sense.

 

I have total confidence in KCL , but I wanted to prove to myself that I could figure out where to put the probes and that I had got the wiring correct.
I had to watch a few videos to finally get it correct and I still have to stare at a breadboard for a while before placing the probes. I need the practice.
I was able to accurately measure the current on each leg.
I was also trying to figure out the total current through 2 legs. That I did by removing the 3rd leg.
And yes, that is close to the schematic that i used though mine was the same one but showed the current as
I1+I2+I3. I tried to figure out how to measure the current through legs 2 & 3.
I hope that makes sense.

The easy answer seems to be measuring current (or measuring voltage and calculating current) for each resistor in question and then simply adding the values together.

However, if you want to measure current through any two resistors at once, break the connections for the resistors in question where dl324 has put the red circles on the drawing, and join the resistors and one of your meter probes together, then connect the other meter probe to the node they previously had in common. Of course, you can do the same thing with the breaks on the other sides of the resistors, as long as they match (all breaks above, or all breaks below.)