# Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

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### 2 mesh circuit giving me trouble. (steady-stade, mesh current method, dependent current source)

The task is to find Ic in phasor form. The circuit is in steady sinusoidal state. I used mesh current analysis and I got to that: I have no idea how to keep ...
599 views

### What is the formula for calculating the no load current of a 3-phase motor? [closed]

I am looking for the formula, not a rule of thumb. Is there a way to calculate the no-load current?
188 views

### How to connect multiple sensors to single PLC input?

Hello. I have a scenario where I have multiple PNP "error signal" from several sensors (let's assume 3 for now). If the sensor output is HIGH, then there is error. If the sensor output is LOW, then ...
47 views

### Current transducer - understanding of turns ratio connection

I'm using a LEM LAH 25-NP current sensor and I don't understand the recommended PCB connections in the table from the datasheet. I understand the first one, but what is with the second and third? What ...
189 views

### Why does the IC not respond (INA200)

The questions I have: Is the makeshift IC I use in the simulation a fair representation of the INA200? I assembled the circuit as shown in the picture (except for the current source and the LED) and ...
1k views

### Why does the measured current differ from the calculated current in this circuit?

I have the following schematic: Now I want to know the (more or less) exact current flow in my circuit. For this I did the following calculations: I = V / R I = 5V / 330 Ohm I = 0.015A = 15mA So ...
59 views

### Is that any best way to measure High side mosfet drain current?

To be specific, I am using 6 MosFETs (for ex. PSMN030-60YS) to drive an inductive load. I want to measure drain current of High-Side MosFETs. The way I am doing right now is by lifting the MosFET ...
226 views

### Electric current in mic

For a typical mic a singer uses in a concert, how much current is generated when the singer sings? The current transmitted from the diaphragm into the wire. What does the following specification tell ...
143 views

### Can I make a ammeter using a voltmeter and ohmmeter that would work in parallel to the device?

I had this small question today when working with an ammeter. Since an ammeter must be in series of the circuit, I had to constantly break the circuit to take current readings. Whereas, when using the ...
97 views

### How to measure current to detect motor stall on H-Bridge driven motor?

I have DC motor with a gearbox to transforms the rotational movement to linear movement and movie a pin back and forward. I need to know when the pin reaches the two positions: full back or full ...
63 views

### Understanding current transformer dimensioning, winding resistance and load resistance

I am looking at this current transformer. What I am trying to understand is the following: Can the burden/load resistor of a current transformer take an arbitrary value? What are the limits? Does ...
101 views

### How to measure currents between 0.1mA and 100mA? [closed]

Summary of question: I need to measure (using a microcontroller, not via a meter) currents between 0.1mA and 100mA, with a reasonable level of accuracy - say, to within 0.2 of a mA. My power supply ...
132 views

### In measuring relay contact resistance, should I use 4 wire measurement or calculate it using the voltage across the relay and current?

I'm reading mixed things online where a current from a typical ohmmeter is too low to accurately tell us the true resistance of the relay contacts. I've got a 30V 2.5A power supply, electronic load, ...
734 views

### Why not use a diode instead of a resistor for current sense circuits?

We're building a motor-drive circuit using an L6206 dual H-bridge circuit. The bottom side of its H drivers come out of a pin called $V_{sense}$, intended to be connected to ground or to a low-side ...
75 views

### What is the source of noise in this current measurement?

I'm measuring the current through a 100W motor with a 50A current sensor and I'm getting reasonably good data but there's also a fair amount of noise: This is the current sensor I'm using. It ...
165 views

### INA168 vs INA169 High-side current sensing

I have read the datasheets of the INA168 and the INA169 and can't see any difference, other than internal resistors value and quiscent current (25uA for INA168, 60uA for INA169). Those two were even ...
105 views

### Where did I miscalculate ohms law in my experiment?

I thought I finally had a grasp on how ohm's law works but when I set up an actual experiment, the numbers don't match up. To keep a long story short, I converted a computer power supply into a lab ...
229 views

Depending on the configuration, PLCs can often measure 0-10V, resistance or 0-20mA on the same set of screws. How to use the same screw terminal to measure resistance of an NTC element, voltages in ...
88 views

### Current monitor circuit not working

For part of a project, I am needing to monitor the current draw of 4 low power loads simultaneously. I like experimenting with circuits and I found one online in a TI application note (AN-31 page 35) ...
165 views

### High side current sensing

I want to sense 30 amps of current using op amp in high side. I know that there are many dedicated current sensing amplifiers for this purpose. But I'd like to try it with an op amp. I have tried high ...
217 views

### Measurement of current with hall effect sensor

I have a setup using 3 hall effect current sensors and my goal is to measure the DC current flowing through cables. The sensors are HSTS016L. I attached a picture of the manual. The sensors have 4 ...
89 views

### When I checking the hot terminal in the socket, multimeter shows the current through me?

I set my multimeter in AC voltage measurement, connected + wire of multimeter to the hot terminal of the electrical socket, and take - wire in my hand. Now it measures the voltage. This procedure ...
118 views

602 views

### How Much Current is Usually Used with IR Transmitting LEDs, in Remote Controls?

If you take various Remote Controls from your home, such as for a TV, Audio System, TV Box, etc, and measure the current that is supplied to the IR LED in the remote, what would be common current ...