Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [clamp]

56 questions
10
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3 answers

How to avoid or compensate for reverse biased base-emitter breakdown in this BJT active clamp design?

This active clamp design is elegant and simple, and works well to prevent OUT from exceeding the supply voltage (+15V), but fails when IN is low enough to reverse bias Q1's base-emitter junction beyond its reverse-breakdown voltage. When this…
Simon Fitch
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1 answer

Why is a clamp meter unaffected by nearby wires?

I understand a clamp meter works by measuring the magnetic field generated by current flowing through a wire. It's well known that clamping 2 wires carrying the same current in opposite directions will show a null reading because one magnetic field…
Zmaster
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7
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8 answers

Can I build, or is there such a thing as an AC clamp multimeter which does NOT require a line splitter?

I am not an electrician. I need to verify the power consumption (watts) of some home equipment (on 120V or 220V) without disconnecting them or splicing the wires. I would love to be able to walk to one of these (network switches, computers,…
Vincent S. Cojot
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5
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5 answers

I am measuring a 9W LED with a clamp on ammeter. Why does it only draw 7.62W?

I bought a UNI T UT210E true rms multimeter. I measured the current of 9 W LED lamp. It shows 0.033A. For the power I get \$0.033 A \cdot 220 V = 7.26 W\$ only. But bulb was 9W. Why this difference comes? Actually am new to electric. I measured…
sss
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4
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1 answer

Is AC current clamp meter accuracy affected by the inner wire curving around the outside?

I have a SCT013-030 current clamp sensor I plan to use to read out the power usage of a mains AC load. It works by wrapping around one of the AC strands of wire to measure the magnetic field. The one I bought is calibrated so that 0-30A is 0-1V with…
bergerkiller
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4
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1 answer

How to select a diode for a Baker clamp?

What are the requirements when selecting a diode for a Baker clamp circuit? How does the reverse leakage current of the diode affect the circuit? Can a diode with relatively high reverse leakage current (e.g. in mA range) turn the transistor on…
Microsoft Linux TM
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How can I clamp the voltage precisely from the back EMF of a brushed DC motor?

I am using DRV8412DDWR in a medical product, where we are driving two DC motors (graphite brushed) bidirectional using PWM. In our application, we have to suddenly stop the motor. When we do that, we are seeing a back EMF current of ~1 ampere due…
Nice Guy
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3
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1 answer

Proper burden resistor CT clamp

I'm trying to figure out what the proper burden resistor I should use, but the information I'm reading from OpenEnergyMonitor answer for the proper resistor values doesn't match what I was expecting. So I'm using YHDC SCT013-000, which has a rating…
used_up_user
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1 answer

Can I measure multiple wires (same current direction) with a clamp meter?

I have two wires that have current going in the same direction. Can I put them both between the clamps of a current meter and read the sum? Edit: I should mention that both wires carry DC current, and I have a clamp meter that also measures DC.
HYQ
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Clamp meter readings

I have a Uni-t UT210e clamp meter. I noticed that when measuring AC current, the reading varies if I move the wire inside the clamp. The measured value displayed on the meter is higher when the wire is closer to the upper part of the clamp, and it…
beard999
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3
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Looking for a 15kV Zener - or equivalent circuitry

I have a high frequency high voltage module that puts out about 15kV (not the stun gun modules sold on eBay). Because of the circuit design the transformer is damaged if it does not arc over. I am looking for a method to limit the voltage when I…
Dirk Bruere
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2
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2 answers

Understanding input bias current in operational amplifier

In order to prevent overvoltages on my arduino voltmeter (more than 20v) I decide to add a protection circuit. As i show in the image i use a AD8605 precision op-amp for the…
marcosbc
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2
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3 answers

Measuring RMS power output from audio amplifier channel

I am looking for a simple way for getting the RMS power output of an amplifier channel set to some arbitrary gain. I want this in order to find the maximum level I can safely set the amplifier at for a speaker with a given continuous power…
user2418372
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TL431 / TLV431 supercapacitor voltage clamping circuit

I have a question regarding a circuit I've been working on for some time. The circuit is based around existing supercapacitor protection modules and uses a TL431 (actually a TLV431 lower power version) precision Zener device. Basically, the…
Ryan Barrett
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1 answer

Clamp a D/A to prevent output below 0V

I am using a USB D/A converter to drive a high-voltage op-amp with a signal between 0 and 3V at 10 kHz. The D/A I am using is capable of outputting between -10 and +10 and unfortunately seems to always output a 1 ms long glitch of -10.7V around…
Kevin Morse
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