Measurements of the current flowing through a circuit

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71 views

DC non invasive power measurment

For one of my PhD project I have to measure power consumption from different electric wheelchairs during various tasks and recor these measurment for later studies. I have not much experience in ...
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1answer
47 views

Measuring current using low side shunt method (MCLV-2 board)

I am trying to measure the current through the MOSFET switch M1 using low side shunt resistor method (on MCLV-2 dev. board). I can read the signal `Vout' on the analog input of a dsPIC33F MCU. I ...
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1answer
48 views

chosing the right Hall effect sensor

For a student project, I need a Hall Effect current sensor. What I am going to do is to charge 8 rechargeable Li-Ion batteries of 3.7 volts in series with 34 volt supply and the buck circuit frequency ...
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2answers
79 views

Drive DC Motor with H Bridge(H Bridge turns off too slow and problem with current monitor)

I have two questions about my circuit, drving DC Motor with H Bridge. The picture below shows my design and how I drive it with signals. For example, when I make the motor rotate forward, I give ...
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0answers
38 views

variable gain amplifier for ACS712 current sensor

My project requires measuring current ranging from 30mA to 500mA. Im using ACS712 (5A)current sensor for this purpose. Since the sensitivity of the sensor is typ:185mV/A, measuring current as low as ...
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0answers
81 views

How to measure microvolts of electricity in plants?

I'm trying to measure electricity in plants, to do something a bit like this: http://www.treehugger.com/culture/organic-electronic-sounds-from-plants-sonic-artist-mileece.html Basically, plants ...
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1answer
22 views

Fundamental difference between DC IV measured current leakage and AC CV measured conductance

I am a physicist with an general EE measurement question, thanks in advance for the advice! I am measuring the properties of a majority carrier diode that I am designing, and usually just take DC IV ...
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0answers
29 views

connecting AC signal 250V to DC signal 3V3

I want to measure an AC and DC current about 250V for AC and 3V3 for DC, i want to use an LT1787 (High Side Current Sense Amplifiers) with amplier stage and DSP to acquire the value. The problem is ...
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1answer
54 views

Buffered feedback circuit analysis

I saw this circuit while going through some circuits and have been trying to solve it since. I get confused at multiple points while solving for the current. Since there is a buffer for ...
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1answer
61 views

how to resolve LM358's huge error as a current sense differential amplifier

Ive built a current sense differential amplifier that measures the voltage across a 1 Ohm resistor to give me a reading for the current through it. Ive connected it as follows, all resistors are ...
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2answers
38 views

Confused about this KVL equation (AC circuit)

I have the following circuit below, with part of the solution: I need to find Z. I'm confused about the KVL equation below (fourth line): If I understand correctly, they used loop analysis: with ...
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1answer
22 views

Peak current requirement for switching logic

Is there a way of estimating peak current requirements for sets of logic gates? This is to qualify the regulator. I have a Gumstix Parlor board with a 1.8V regulator (MIC5247) at 150mA on it. This is ...
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1answer
59 views

Measuring GameBoy power consumption

I am currently developing my own homebrew GameBoy game and I would like to try some tricks to reduce power consumption (for the sake of learning). The GameBoy has a HALT instruction that will stop ...
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1answer
51 views

LM311 Current Sensing Switch

I need to create a current sensing switch and am looking for ideas. I have very little experience with op amps / comparitors (as you'll see) but this seems to be the way to go. I am monitoring 24VDC ...
4
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1answer
69 views

Recommended Layout for Parallel Current Sensing Resistors

I'm working with 12V DC systems and high currents (up to ~40A). In order to meet the wattage and price requirements for my design, I'm using two parallel sense resistors. The IC I'm using for sensing ...
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2answers
80 views

How to measure current with an analog multimeter? [closed]

I need measuring the current through a dc motor with an analog multimeter, but I don't know how to select the correct function to that. The meter is a FT-360TR. I know it can measure currents of ...
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1answer
61 views

3A Current Distribution

simulate this circuit – Schematic created using CircuitLab I am using a 5V 3A wall adapter. I have stripped the output end and connected it to a terminal block. I am rerouting the current ...
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1answer
59 views

Usb input current requirements for a power bank

My project is to take solar power from a 6w/6v panel, run it through a buck circuit tuned to 5v and charge one of the LiPo power banks. I perceive a buck circuit would do better at efficiency than a ...
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1answer
30 views

Computing Power Requirement For Solar Setup

In relation to this question: Solar power wattage requirement I'm trying to get to the math of understanding my wattage for my plan solar-setup. I would like anyone here who knew can correct me on my ...
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1answer
307 views

Converting 100mV AC to 1V DC

Hey guys I am looking for a circuit where I can convert 100mV AC to 1V DC and then feed it to my microcontroller's ADC pin. Can any one suggest any circuit to achieve this? I want to interface a ...
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0answers
44 views

Peak and leakage current detector

Hello I am trying to make peak and leakage detector for LCD shutter. I have specific parameters known : Voltage from 5V to 12V bipolar square wave. Testing is at 60hz Peak current ~30mA leakage ...
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1answer
66 views

Short circuit current in transformer

When transformer secondary is short circuited, what would be the value of current flowing through short circuited side? Shouldn't it be infinity ideally? If yes, is it only due to large cross-section ...
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2answers
70 views

Wiring an ammeter with no shunt [closed]

I am new to electronics and trying to make something easy to start with. Bought one of those voltmeter and ammeter AIO from ebay (LINK , see item #5) and want to hook it to a 12V battery (4Ah) to ...
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2answers
69 views

measuring the current for battery monitoring project

I have to build up a battery cell(single) monitoring system which can calculate the cell's (single) efficiency which should be atleast 0.1% - 0.5% accurate. The cell would be charged over a couple of ...
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1answer
60 views

ZYNQ ZC702 measurements of current

I need to measure a current with the osciloscope on a ZYNQ ZC 702 board and I do not know what shunt resistor should I pick. I am not so good at electronics so if some one can help me I would be very ...
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4answers
81 views

Am I reading my multimeter correctly?

I'm trying to wrap my head around the 20m and the 2000µ setting. On 20m I see 0.01 but on the 2000µ setting I see 005. Does this mean my circuit is using 5µA of current? Why the discrepancy?
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4answers
2k views

Is current flowing backwards a bad thing?

In the circuit below: I find it awkward that the direction of the current on the 2V power supply is running opposite to the direction of the current on the 5V power supply. In the 5V power supply ...
0
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1answer
99 views

measuring microampere current without noise

I have a constant current source that can output current in the range of 0mA to 1mA. I am driving 100 microamps through a load resistance (1.5Kohm) and then connected another test resistor (1.0 Kohm) ...
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1answer
95 views

Can I measure inductor current by adding a secondary winding?

I have a buck converter and I want to add a current loop to it. I don't want to use a hall-effect sensor or something expensive like that. I think it is not practical to use a sensing resistor since ...
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2answers
122 views

Problems amplifying mV potential differences

I am trying to help my daughter with her science fair project of measuring efficiency of different types of household lighting in various heating conditions. Since she doesn't have the electronics ...
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5answers
106 views

Why does ammeter or voltmeter measures RMS value

When there's an alternative voltage, why does the voltmeter measures rms value instead of the value at that specific time?
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2answers
70 views

Current transformer not sensing currents

I have made a current sense transformer to sense primary current maximum 2A(of my electric iron) and secondary output is 1A but there is no current in the secondary. I have used a iron "Nut" as a ...
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3answers
155 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 ...
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0answers
44 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 ...
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3answers
227 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 ...
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1answer
63 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
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1answer
45 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 ...
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3answers
205 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
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4answers
681 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
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3answers
272 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 ...
2
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1answer
88 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
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1answer
226 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 ...
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2answers
91 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 ...
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1answer
70 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 ...
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2answers
124 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 ...
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2answers
275 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
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1answer
161 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 ...
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1answer
68 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 ...
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1answer
53 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 ...
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2answers
101 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) ...