I find the RLB references humorous because RLB is my initials.

Resistor Load Bank (RLB)

 

Like I mentioned, I said I will keep a constant 5V and only vary the current through all that Resistor Load Bank (RLB).

Please tell I am not reading this correctly — that you don’t really think you can keep 5V across a resistive load and vary the current.

 

Please tell I am not reading this correctly — that you don’t really think you can keep 5V across a resistive load and vary the current.

You saw where I questioned that. It's above my pay grade.

Ron

 

you don’t really think you can keep 5V across a resistive load and vary the current.

if you folowed me along, youve seen I already did that but in a very special case, when no component in test is connected to the load. When only a wire is connected . This way I could program all those nice values you've seen in the movie, the 1, 10 and 100's.
But in the moment I connected the component in test, the whole idea crumble because the voltage changed through voltage dividing.
And thats it. I can not make it. This project is done, since I can not measure reliably anything except a wire, or anything close to a wire that is not dropping any voltage over it, or next to nothing.

 

I start to believe, maybe this resistor Load is meant to be used only on very special circuit like the testing PSU that @Reloadron mentioned he originally used it.
What are other usages for this specific Resistor Load? in practice. And where could I possible encounter it when I was too young to remember anything? in the 80's and 90's.

 

While the testing of various power supplies is the most common use we also have used them to test generators and alternators which in a sense are power supplies. That's about all I can think of at present.

Ron

 

Thank you !

 

if you folowed me along, youve seen I already did that but in a very special case, when no component in test is connected to the load. When only a wire is connected .
…
But in the moment I connected the component in test, the whole idea crumble because the voltage changed through voltage dividing.

So when you replace a wire with a resistor, you expect the voltage and current to remain the same?

 

So when you replace a wire with a resistor, you expect the voltage and current to remain the same?

Is not what I expect, is what I observe. It is the same over the 1R shunt, when is in wire mode. But not when I replace the wire with something else, a tr, a diode or another res. It goes into a voltage divider mode. Which it was not very clear with the opamp cct, but it is very clear, right in your face clear, with the Load res bank cct. In this case, this voltage divider that is formed, is an obstacle for what I wanted to obtain.
But I think I start to realize a very easy and cheap way to measure a component. Connected directly to my varPSU. Although I had some minor fluctuations from setting it and is a bit unstable - maybe the knobs are dirty or just it fluctuates with increased temperature, but it is a minor fluctuation that I can overlook. I think. More testing required. with more components. So far I did 1 succesful test with a BC548. I have to test other more powerful tr's, and also some mosfets. But my solution I propose here is very easy to do.

 

You still seem to be saying you can make two different currents, say 1mA and 10mA flow through a 1Ω resistor without changing the voltage across that resistor. Is that correct?

 

if Im changing the resistors yes. Or the pot of the current source with the opamp.

 

".....you can make two different currents, say 1mA and 10mA flow through a 1Ω resistor without changing the voltage across that resistor?"

" if Im changing the resistors yes."

No you can't.

 

Apparently, this project was doomed from the start. That damned Ohm’s law got in the way.