Measurements of the current flowing through a circuit

learn more… | top users | synonyms

0
votes
3answers
108 views

How to measure nano-amps easily?

I want to measure the stand-by current of the PIC, but my DVM has minimum 2000micro (u) amper switch. It shows 0 micro amps when in 2000 u amps mode. Without building circuit a complex (more than 3-4 ...
0
votes
0answers
30 views

Discarding Current Monitor of Linear's LT3482

I've been looking at the LT3482 IC with an APD/Photon Counter application in mind. I need to bias my APD at something like ~65V to reach Geiger mode. Since I've already have a non-inverting ...
1
vote
3answers
173 views

Current Divider Formula Proof

Just recently, I was watching a video where the presenter used a current divider formula (I think he called it the "G" rule) to calculate the current flowing throw a resistor on a circuit with two ...
1
vote
1answer
58 views

how to calculate the current in this circuit ( opamp)

how to calculate the current in this circuit (show with the green arrow) Can someone explain with a bit of details. In the books i got from school, they dont come close to what this looks like.
0
votes
1answer
41 views

can an ammeter damage zeners

So I got this small circuit that plugs to the mains as power source. as for its DC converter, it's one of those transformer-less ones that drops the voltage with a resistors and filters before ...
1
vote
3answers
108 views

Wheatstone bridge why not use a voltmeter?

I have been reading up on the limitations of a Wheatstone bridge, one of which is that for high bridge resistances any imbalances are hard to detect because of the small current that flows through the ...
2
votes
4answers
441 views

Using two 14 AWG wires instead of one 12 AWG

I do understand there are many factors when choosing what AWG wire, however by the charts, tools, and info I have found, using two 14 AWG copper wires should be equal to a single 8 AWG wire. 8.025 AWG ...
6
votes
3answers
253 views

Ammeter time limits - how to understand them [duplicate]

On my multimeter, near the 10 A connector it says 10 A MAX 10sec EACH 15min. I usually measure currents less than 1 A so I never cared about this. Is it correct ...
1
vote
1answer
63 views

How can I measure the current drawn by a soil hygrometer?

I have one of these ubiquitous soil moisture sensors: The only information I can find is that it operates from 3.3V to 5V, uses an LM393 to trigger a digital output and also exposes an analogue ...
0
votes
1answer
84 views

How do I detect servo stall with an Arduino?

I am controlling a standard 5-volt servo with an Arduino with PWM. My objective is to rotate the servo until it physically gets stalled (feels resistance) and then stop. Then I want the Arduino to ...
0
votes
2answers
78 views

How to detect current imbalance?

I would like a circuit that detects current imbalance between two conductors. The currents are normally equal and opposite in direction, but can vary in time (or reverse direction). Neither ...
1
vote
1answer
42 views

CCVS (current controlled voltage source) in practice

In my current project I'll possibly need to deploy a CCVS (Current controlled voltage source). It is transconductance amplifier or converter and many manufacturers offers transconductance amplifier ...
1
vote
2answers
69 views

Why are null measuring methods considered to be very precise?

I heard a professor saying "it's a null method, so it is very precise". He was talking about the force balance pressure measuring method. I think in this cathegory of methods one can include the ...
0
votes
2answers
232 views

How to sense current with OPAMP?

I want to sense the current that battery supplies to the low current (few mA) circuit. As everyone said before, forcing discrete design does not make sense, so I decided to apply simple OPAMP & ...
0
votes
1answer
62 views

Current Sensing with ACS712 on Beaglebone Black

I am planning to use my BBB to perform some current sensing and was wanting to use the ACS712 chip. The chip operates off of 5V, but the analog inputs of the BBB have a max of 1.8V. How can I wire ...
0
votes
1answer
41 views

Understanding High Side Current Sense OpAmp Datasheet

I'm considering the INA199A3, AD8293G80 or TS1102-100 (decreasing cost order) for a high-side current sensing application. According to my understanding the output voltage error is mainly affected by ...
0
votes
1answer
37 views

Si8519 AC Current Sensor usage

I'm trying to find a good and practical current sensor and I found this: Si8519 http://www.silabs.com/Support%20Documents/TechnicalDocs/Si85xx.pdf My idea is monitor AC Mains current, so this Si8519 ...
1
vote
2answers
91 views

Measuring Electron Beam Currents

When it comes to measuring electron beam currents with a Faraday Cup (or any that will pick up electrons and act as an anode), primarily AC and transient signals, my understanding is that one can (1) ...
1
vote
0answers
125 views

Reduce analog reading noise on arduino

With refer to this question: I got CTs connected to all analog pins on a Arduino Mega, connections for each pins are as mentioned here. Readings were good indoors, +- 0.1A. However, when located ...
0
votes
3answers
96 views

How is a transconductance amplifier used to measure current?

In this post Design for a Precision LCR Meter the author says: Current is measured via a transconductance amplifier (again with programmable gain) which produces a voltage proportional to the ...
1
vote
1answer
76 views

Current sensor with instrumentation amplifier (LT1167)

Objective I'm trying to make a current sensor that can accurately measure current up to 5A. In order to do this I'm using an instrumentation amplifier (LT1167) to measure the voltage difference ...
3
votes
2answers
114 views

How do I design a current transformer?

I want to make a Current transformer using toroidal ferrites to measure 220/50-60Hz AC current(40A max). Is it possible? And how can I calculate secondary turns count? Ferrite properties: H = 2000, ...
2
votes
2answers
135 views

How much current does a typical multimeter draw to measure resistance?

Assuming it's running on a 9V battery like most multimeters are, and the setting is on MegaOhms. How much current will be drawn from the internal battery?
0
votes
2answers
87 views

Series RLC measurement result different with theory

I am measuring the current and voltage in simple RLC circuit: However,the result that I measured show big difference with the simulation result using Multisim. Why is there are a big difference ...
-5
votes
1answer
52 views

Calculate Current [closed]

how to i calculate current( Before Resistance ) from these parameters Voltage before Resistance Voltage after resistance Resistor Value Current After Resistance
5
votes
1answer
335 views

What causes inaccuracy over time on a DMM?

Here is a piece of information from a datasheet of a DMM. The accuracy rates seemed interesting for me. I wonder what causes difference in the accuracy, especially the changes after 24 hrs? Is it only ...
0
votes
1answer
231 views

How much power does a wireless mouse use? [closed]

I have seen many answers online to how much power the USB dongle linked to a wireless mouse uses, but nothing about how much power the actual mouse draws from its batteries. What is a ball-park ...
0
votes
0answers
100 views

Voltage/current Monitoring - MAX4172 + ADC vs. INA219

I'd like to add some monitoring of voltage and current on the +5V and +3.3V supply rails of a development board power supply. I'm currently debating between two approaches. The first approach is to ...
2
votes
4answers
644 views

Current sensor measuring circuit

I am planning to design Rshunt basis current measuring. My current measuring range is 1A~2A. I need analog output of 0~5V analog with 1% accuracy. How can I do this? I found conversion circuit here. ...
0
votes
1answer
99 views

milliwatt-hour meter [closed]

I am looking for a way to design something that can tell me the cumulative power draw of a circuit -- the same concept as a Kill-a-Watt, but measuring mWh rather than KWh. An added bonus would be the ...
0
votes
1answer
58 views

How do I place a long wire to make the EMI and inductance minimum?

I'm going to measure high current. After seeing that there is not a lot of low valued sensor resistors in the market and the available ones are very expensive, I decided to make my own current sensing ...
0
votes
5answers
185 views

ADC implementation

I want to sense the voltage across the resistor R1 (i.e convert it into digital form). I only have comparators available with me and no other hardware (ADC is not available). Is there any way I ...
0
votes
1answer
78 views

measuring current to 100uA accuracy in a battery powered circuit

I'm trying to figure out the best way to measure and log current consumption in my circuit, which houses an ATMega2560 and a number of sensors and servos. Using a DMM, I see about 100mA draw when ...
0
votes
2answers
138 views

Known voltage/current source

I am working on an EVM for an electricity meter. Its manual says the EVM requires a known voltage and current source for the calibration. I bought a power supply and measure the output of the PSU by ...
2
votes
2answers
82 views

Inductors in series with different currents

I'm having trouble finding the differential equation that describes the circuit, at t=0 10A flow through L1 and 0A through L2, since current can't change instantaneously. But they're in series so ...
2
votes
3answers
464 views

How much current is a powered-down ATtiny84 supposed to take?

I know this sounds like a stupid question, but I'm wondering if the datasheet has an error or something. I have an ATtiny84 connected to my bench power supply set for 3 volts. It's fused for the ...
0
votes
1answer
59 views

Three phase motor current verification

I want to verify that the quadrature current through a permanent magnet synchronous motor (PMSM) is actually the same amount as I commanded the field-oriented control (FOC) motor controller to push it ...
1
vote
4answers
244 views

How do I average a complex waveform?

I am trying to figure out how long my project will last on a single battery. It's powered by a single AA battery with an NCP1402 3.3 volt boost converter. I've determined that the target circuit draws ...
2
votes
2answers
342 views

Solar power monitoring with Raspberry Pi

I want to measure the current and voltage from a set of small solar panels (about 10V and 100mA but not settled yet) using a Raspberry Pi. There will be between 4 and 6 panels. This project will ...
0
votes
0answers
122 views

How to measure the peak current (inrush current) and results assessment

I would like to peak the inrush current of a controller. The voltage input of the system is 24V and the only thing which is available, is an oscilloscope and a variety of resistors. The basic idea is ...
0
votes
4answers
159 views

Is it possible to power AVR micro project with just one coin cell battery?

My current project setup is: ATmega328P micro with 32 LEDS driven by 4 8-bit shift registers. System without LEDs draws 20mA of current continuously. With all LEDs lit at the same time, it draws ...
0
votes
0answers
90 views

DC shunt current measuring

I am trying to build DC shunt based high current measuring using bus bar. Each bus bar has a 1000V 20A rating. Is any IC available to measure? I have done with hall sensor based. So my plan to build ...
2
votes
2answers
984 views

calculating a burden resistor for a current transformer

Background: I follow a reference design for a single phase power meter (230V, max 3A). The below circuit is to measure current via a current transformer. a CT will be connected to...
18
votes
1answer
1k views

What are the advantages of a shunt resistor vs. a hall effect sensor?

I'm constructing a boost converter, and I need to measure both the input current and the output current. Currents range anywhere from 25A to 200A, depending on the model. My controller is referenced ...
0
votes
0answers
47 views

Determine current so that you have circular polarization

I have a problem in resolving the first point of exercise on antennas. Note: if it wasn't clear \$\phi_1\$ and \$\phi_2\$ are phase of alternate currents \$I_1\$ and \$I_2\$ I know that to have a ...
2
votes
3answers
1k views

How to build very low cost current transformer?

Im building low cost home energy monitoring system. I want to see how much energy is used by water heater, big water pump, kitchen equipment, lightning, computer. I would be awesome if I could measure ...
2
votes
2answers
105 views

Simple PWM regulator, current measurement without high-side current sensing

I have a very simple Lead-Acid battery charger with slow (1kHz) PWM regulator. I would like to add current and voltage measurement (with PIC18F ADC - 200kSPS). I have no problem with voltage ...
1
vote
2answers
273 views

Measuring Current Consumption of USB Devices

I was trying to measure the current draw of a USB-powered device (a Raspberry Pi) to determine the suitability of powering from an external battery pack. So I took a USB cable, split the +5v (red) ...
-1
votes
2answers
1k views

RMS vs DC(mean value) when calculating power of pulsed or rectified signals

When I have either a rectified signal (like the unfiltered rectified sine wave out of a diode bridge) or say a fast pulsed signal feeding a LED and resistor, in which both the DC component and the RMS ...
0
votes
0answers
488 views

How to measure current waveform in Proteus?

How are current waveforms measured in Proteus? There is a current probe in Proteus but I think it is giving me absurd results. I want to plot the current flowing through a resistor. There is a graph ...