8 votes

How do I tell if a shunt resistor is routed using the Kelvin method?

The main goal of a Kelvin connection is that potential drops in the wires delivering the current to the resistor don't get measured as part of the resistor drop. That means that all of your examples ...
The Photon's user avatar
  • 130k
7 votes

Measuring nA leakage current

My issue is my meter's measurement accuracy is only around 10uA, Maybe on your lowest current range perhaps. Have you looked carefully at what your lowest voltage range will do? I have a cheapo 3.5 ...
Neil_UK's user avatar
  • 167k
5 votes

Measuring nA leakage current

Is it possible to reliably amplify this current to a measurable value, or perhaps convert it to a voltage using a potential divider, while still getting an accurate measurement? Yes, this should be ...
Voltage Spike's user avatar
  • 82.7k
5 votes

Measuring the resistance of an LED -> getting conflicting values

A red LED at reasonable current levels has a voltage drop of about 1.8V or 1.9V. So with a 3V supply and 100Ω series resistor we would expect a current of about (3-1.8)/100 = 12mA With 200Ω series ...
Spehro Pefhany's user avatar
4 votes

How do I tell if a shunt resistor is routed using the Kelvin method?

I would dare say neither; this option seems to have been overlooked: But this still isn't actually much better. The reason is, a Kelvin connection is only defined for the device it's calibrated for. ...
Tim Williams's user avatar
  • 34.2k
4 votes
Accepted

Measuring the resistance of an LED -> getting conflicting values

I couldn't find the resistance values for an LED so I tried to measure it An LED isn't a resistor, and won't behave linearly the way you're expecting it to - your mental model is flawed and Ohm's Law ...
Attie's user avatar
  • 1,831
3 votes

Measuring the resistance of an LED -> getting conflicting values

A LED is not a resistor so it won't register with a multimeter to a resistance value. As a first order model, an LED has only a forward voltage (Vf) drop. If you look at the I-V characteristics of a ...
winny's user avatar
  • 14.8k
2 votes
Accepted

How can a current probe avoid saturation?

You cannot use a transformer (whether or not a current transformer or Rogowski coil) to sense or measure DC current. That being said, there is a trick you can use if your buck converter is operating ...
Math Keeps Me Busy's user avatar
2 votes

Measuring nA leakage current

I have designed ICs with a quiescent current in the 300nA range. The tricky part is that this isn't a constant current (long times of low current with very brief high current spikes every 100ms or so)...
mapplejacks's user avatar
1 vote

High current/voltage power monitoring in small form factor

You need to read datasheet more carefully. The nominal input of current ADC is +/-1V and the maximum is +/-2V. The shunt is 2 mOhm, not 2M. This means nominal peak current of 500A and absolute maximum ...
Maple's user avatar
  • 12.6k
1 vote

Getting different answers for number of electrons in 1 amp?

1 amp for one second is a charge of 1 coulomb. Given that a charge is made up from electrons, the total number of electrons involved in the flow of 1 amp for 1 second equals 1 coulomb divided by the ...
Andy aka's user avatar
  • 457k
1 vote

How can a current probe avoid saturation?

As you seem to be interested only in the AC part of the current and saturation is your specific problem, changing the current transformer to a rogowski transducer sounds like the obvious replacement.
tobalt's user avatar
  • 22k
1 vote

How can a current probe avoid saturation?

How can probe avoid saturation? Yes, it can be a problem. For the AC part it isn't a problem because the ampere-turns on the primary are cancelled by the ampere-turns on the secondary. So, the only ...
Andy aka's user avatar
  • 457k
1 vote

Microcontroller that can do 10 UART?

Got a datasheet... "The library of PZEM-004t V30 works on hardware serial as well as software serial." Looking at the source code... The microcontroller sends a command to the device, which ...
bobflux's user avatar
  • 77.6k

Only top scored, non community-wiki answers of a minimum length are eligible