All Questions
Tagged with measurement current
67
questions
5
votes
1
answer
124
views
Can I use 12 V and -12 V together?
I am sorry if this question is pretty easy but I am a beginner.
I have a PC PSU that provides two lines:
12 V 11A
-12 V 1.5A
If I used them together will I get 24V, and how many amps can they provide?...
0
votes
0
answers
32
views
How to eliminate internal circuit current consumption from the measurement in bi-directional current measurement circuit?
I am comparatively new in this domain. I am trying to design a bi-directional current measurement circuit. This is a 5V to 9V DC system. I have two USB C female ports at both ends. Which means I can ...
0
votes
1
answer
56
views
Current measurement in every 20ms
I want to measure the current in every 20 ms and record the measurement. I was using the Fluke DMM and in that I am not able to measure something less than 125 ms. Could someone suggest any methods ...
- 101
0
votes
0
answers
46
views
Error in current measurement
I am measuring the error ratio and phase displacement in a CT. The experimental circuit is the next.
The results with the oscilloscope show that the error ratio is not within the limits of the class ...
- 1
2
votes
0
answers
28
views
Is it necessary to implement a sensing resistor plus pre-amp with Faraday cage on a PCB if I would like to have the range about 10nA measurement?
I put a 60 kΩ sensing resistor plus low-bias current amplifier with a gain of 500 into an aluminium bag and tied it to AGND for EMI shielding. The second stage is an ADS1256 24-bit ADC. The purpose is ...
- 89
0
votes
1
answer
461
views
USB meter does not detect current in very basic USB circuit
I have a USB LED light (for plants) that draws 5 V @ 1.16 A when I plug it in, as measured by my USB volt/amp meter.
EDIT: The problem was caused by the specific USB tester model KWS-MX18L. See answer ...
- 101
0
votes
1
answer
53
views
How to calibrate a shunt with a MM and another shunt
I had noticed someone in my lab calibrated a shunt with a MM and another shunt, was wondering how they went about this?
Thank You
- 11
1
vote
2
answers
223
views
Why add extra resistance to a shunt?
simulate this circuit – Schematic created using CircuitLab
I'm using a Fluke Y5020 air cooled shunt (it's 10 mΩ, 20 A max) and putting 3 A at 60 Hz into it.
Aside from Ohm's law, is there any ...
- 11
3
votes
4
answers
881
views
Solving for elements of a conductance matrix, given the voltages at each node
I'm trying to solve for the elements R12, R14, R23, R34 in the following circuit.
Resistances to ground R1, R2, R3, R4, voltages at nodes V1, V2, V3, V4, and input current I0 are all known.
The ...
- 31
0
votes
1
answer
17
views
Calibrating the current (uA) of a TI by using a 34465A DMM as a std and a suitable load
When calibrating a test instrument (TI) on its current generation using the DMM 34465A as the standard and a suitable load in series, I think the uncertainty budget should not include the accuracy and ...
- 1
0
votes
0
answers
218
views
Current measurements - shunt switching
I have been designing a current measuring device, and since it requires high wide-range accuracy, I decided to use two shunt resistors of different sizes. The schematic is shown below:
The design ...
- 237
4
votes
3
answers
2k
views
For measuring a resistance should you use a constant current source or a voltage source?
I need to design a PCB to measure a resistance of around 5 kΩ and a resistance of 0.2 Ω. I don't know what the best solution for measuring these resistances is; maybe a combination of both methods?
To ...
3
votes
5
answers
3k
views
Getting the energy consumption in joules over a period when having current and voltage
I'm trying to calculate the energy consumption over a period of 1.3 seconds in joules (J).
I have a sample every 100 ms (0.1 second) with the current and voltage (in volts) (in practice, the samples ...
- 65
0
votes
1
answer
48
views
How would I be able to measure the current using this setup?
What ways can I measure the current as test points on a circuit?
Would I need to add a zero ohm resistor and solder the resistor for normal operation and desolder the resistor and then place my ...
- 45
0
votes
2
answers
421
views
What are the possible reasons this current transformer doesn't work?
On the assembly shown, I have built a current transformer with a toroid coiled with 30 turns of magnet wire. The brown wire is the phase going through, blue is neutral.
When I connect a fan onto the ...
- 23