In my armchair browsing I recall seeing a Kelvin Shunt to some such that does the same thing... but you explain in amazingly well, thanks! :)
@IMSAIGuy
Жыл бұрын
yes, if you see a four wire resistor, it is a Kelvin shunt
@youtuuba
Жыл бұрын
When Heathkit introduced their one and only digital auto-ranging capacitance meter, the IT-2250, their catalog touted the "Kevin" connector. It must have been a new one on the copy writer, because very few other Heathkit products used a "Kelvin" connector, and they probably just saw the engineer's scribble and "corrected" it to something familiar, "Kevin". But their next catalog, the copy was exactly the same but for the correction to "Kelvin".
@paulcohen1555
Жыл бұрын
4-Wire takes out not only the test wire resistance, but also the contact resistance which is another troublemaker.
@johnwest7993
Жыл бұрын
These are the sort of things that noobs to electronics are often vague about. Thanks for making it clear for them.
@johnjohn-ed9qt
Жыл бұрын
Nice explanation. This video is now on my students' recommended list. It'll save lecture time, and is a better explanation, with the demo, than I can do in the lecture (available tech being what it isn't...) A nice followup might be a remote sense power supply, due to the additional consideration of stability. Thank you for doing these.
@Edisson.
Жыл бұрын
Beautiful explanation and demonstration, everyone must understand that. Nice day 🙂 Tom
@TeslaTales59
Жыл бұрын
"namby pamby wires!"
@TheEmbeddedHobbyist
Жыл бұрын
Folk also forget that a lot of power supplies have 4 wire outputs, where the source and sense are bridged at the pus with a metal link. The idea again being that you can remove the links and run the sense wires to the point of load and remove the voltage drop in the cables. As the power supply will regulate the voltage at the end of the sense wires e.g the load and not at the psu terminals.
@Ziraya0
Жыл бұрын
So, in the diode fixture with the source and sense contacts opposite one another, even though the source and sense contacts are touching the leads at the same distance away from the diode body, the sense wire improves the measurement because it's eliminating all the length of conductor that the source is travelling through inside the machine?
@IMSAIGuy
Жыл бұрын
yes
@robbo6460
Жыл бұрын
So you can use a Kelvin connection to measure voltage as well as resistance? My HP3468A has 4 wire for resistance. Can that be used in other functions with the 4 wire leads?
@Edisson.
Жыл бұрын
Not with a classic multimeter, but there are special devices that allow the use of sense terminals for so-called dual measurement - the display must correspond to this, so you can measure two voltages, or voltage and current separately. This connection is also used, for example, with electronic loads, on my load the switching takes place automatically - if I connect the loaded circuit only to the main terminals, the 2W load works, if I also connect the SENSE input, it automatically switches to 4W and the differences are really huge. Nice day 🙂 Tom
@robbo6460
Жыл бұрын
@@Edisson. thanks for explaining this. I just bought a Keithley 228A voltage/current source and the output card has sense terminals. Those can be run out closer to the load for better more accurate regulation?
@Edisson.
Жыл бұрын
@@robbo6460 I don't know this model personally, but if it has sense terminals, they will serve to prevent the voltage drop on the powered device - example: I have a device with a large consumption, due to the transient resistances of the terminals and the resistance of the wires, the powered device will have a voltage drop against the set one. If I connect the SENSE circuit to the powered device, the source will probably compensate for this drop automatically, or if I need a completely constant voltage without fluctuations - the source uses SENSE to compensate for the drop - since I do not own such a source, the above description is only an estimate from the general SENSE function.
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