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60 Threads found on Coil Measurement
Hello, Is there a recommended way of measuring the parasitic capaictance of an inductor coil or planar inductor? Any advice is appreciated :) Kind Regards Cat
The solution could be a dual channel oscilloscope in differential signal configuration. Common signals should be canceled (if the probes in both channel are identical) but the signal from the coil should be displayed. (This could be a solution in low frequency range, I am not sure if it will be effective at 10 MHz ).
Hi. I've a little practical question. I've measured in anechoic chamber the input impedance of a coil loaded monopole resonating near 487 MHz. I've calibrated the Network Analyzer up to the point where I've attached the antenna. My need was to determine the input impedance of the antenna so I take a measurement of the magnitude and of the phase o
Hello, I found a transformer with cutoff wires, I want to use it , but primary coil has 3 leads: red, blue and brown. So which pair to connect to 220V? Resistance between are as on are there 3 leads, none is connected to the iron core. Thanks.
hi, i need some answer about..... 1)what type of wire or coil is used for the antenna of rf transmission 2)i have collected some wire and made them a loop of square shape and for measuring its inductance applied it in a rlc circuit.but its not showing any significant can i measure the inductanmce of this coil?? i am trying to tran
It does not look like the antenna is a balance sctructure, does it?.........If that is the case you do not need a BALUN. But what it looks weird is the coil you have put in the middle, why? Matching?....You can do with small lumped 402 devices. For other hand the coil and the long thin traces will be part of the antenna. I would recommen
hi guys im not sure if im in the right place here but im kinda stuck on one of my trade test questions that is what causes the difference in current measured and current calculated in an ac contactor coil and explain.. something to do with reactance? any help would be greatly appreciated cheers chris
It should be noted, that the suggested "transformer" doesn't behave like a ususal current transformer. In the frequency range of interest, the said "proportinate voltage" is actually proportional to the current differential di/dt. It must be integrated to achieve a frequency and waveform independet current measurement. Furthermore, the coil isn'
How can I measure the impedance of a small coil like the attached photo? coil is 2mm coper wire located inside a quartz tube (4 mm diameter for water cooling). coil diameter is 2.5 cm and lenght is 2.8 cm both like this and while plasma is ignited and coil is
hello everyone, anyone know what's important we need to calculate single layer air coil inductance and how to calculate air coil inductance? Thanks, kyg
I could be way off on this, but it seems that if you want to measure current, wrap a coil around the hot wire and measure the induced voltage. With a current from 0 to about 2.5 amps you should have no problem measuring a voltage.
how can i measure the inductance of a coil .
i actually did this once, for 600V bridge with 100A throughput. i used rogowski coil as FvM suggest (the green sense wire comes in all sizes). it only measures AC current, so keep that in mind, but it has huge bandwidth. the voltage measurement is tricky.. especially if you want accuracy. the voltage is dynamic and in a high noise environment
Hi, I am measuring the Q factor of a coil with a VNA using two methods. 1 Transmission 2. Reflection Do I need to have an impedance match for the weekly coupled small coils connected to the VNA. According to what I understand, no impedance matching is needed. Is this correct? Many thanks
I'm under the impression, that the pulse CX2041NL may be better suited for 10 MHz range than mini-circuits TCM1-1 due to it's wider frequency range. But basically each of them should work, if you apply standard open/short/load calibration at the transformer secondary. A general problem with balanced network analysis is the unknown common mode to di
A coil placed near the motor might pick up a sinewave by induction. You might have to experiment with different types of coils (low vs. high inductance, containing iron vs. containing none, etc.). You might have to try it in different locations (near windings, near an opening in the housing, etc.).
Please see whether this paper from coilcraft is helpful.
I would like to know how can I measure the ampere of a coil, if for example I know the wattage of the coil is 200 watt and the resistance of the coil is 500 ohm and it works on 24 VAC so how much current will it uses? so i can decide type of cable to use.
I have an Inductor and I ran a scan form 20Hz to 20KHz on an impedance meter and got very strange results. I measured L and |Z| and for starters got very different results than my DVM which is measuring in 270Hz. The plot starts with a value of 770mH @ 20Hz and goes up to around 950mH @ 20KHz, but the higher the freq. the more the inductance change
As you should learn and then find a solution, I can recommend the easiest way (I also worked with shaking tables). Connect an analog sensor to an oscilloscope. Shake the table to see sensor response. As a sensor, you can use a piezo element coupled to the table and its base so it can be lightly bent by shaking. You can use a coil with a magnet cor
The mathematic can be found at Wikipedia Rogowski coils have no magnetic core. HV capability is a matter of insulation, which can be chosen according to your needs. Several application notes and basic literature can be found here See also:
For $20 I would buy the correct one, you need a special machine or a LOT of time to wind toroid coils! Frank
Any body know about how can i measure the load through Mosfet(parallaly connected) without using CT coil and Hall effect sensor . i mean am going to switch this mosfet through 50Hz square pulse and load may be approximately > 2KVA (so shunt res not possible to measure load). i want to know, how to find the load across mosfet .here accuracy is n
Additional to the classic current transformer method, there are now available devices which look like current transformers in that they generally have a toroid form that you pass the current wire through, (optionally with more than 1 turn), but are Hall-effect sensors. Some simply amplify the sample, other more accurate types use a null coil and a
Use a rogowski coil.
If you are operating in sea water, there is a proven method. Naval vessels use a detector called a Rodmeter. The rodmeter is a coil inside a waterproof sheath. On the surface of the sheath are two contact buttons. A constant magnetic field is established by the coil. - As the vessel moves through the water, the conductor (seawater) is cut
You need to put a resistor between the uc and the bjt. This will limit the current and put less stress on the uc. You can use a darlington pair of transistors to get more current gain. As a test, hand hold a wire between the collector and emitter of the bjt and see if the relay closes. You need a diode across the relay coil pointing towards
10 turn coil should have full DC supply voltage if not oscillating. Check 215V supply without a load and when loaded with oscillator. When oscillator is not running it may draw significant current and overload supply. It could be a reason that you have only 100V. The reason why oscillator is not working can be wrong connection of transformer windin
hadef, You can control an AC device using a relay. The important relay parameters are: Maximum contact voltage. Contact voltage ratings are different for AC and DC loads. ~ Maximum load current. Relay current ratings are different for resistive, lamp, inductive loads. ~ The coil drive voltage that is available. Relay coils come in various
Most common way is to use two coils of wire. They must be isolated and work like transformer. Feed first coil with some small AC voltage, measure feedback from second coil. Once you put some metal object near coils you will have a change in second coil output. Size of coils, number of turns, (...)
I use digital meter and when two point is completely electrical isolation than it display "0.L", I always think that. That circuit is the power supplier for computer, it is decayed, I did testing probe on the primary coil of transformer and see that. That voltage is fed from a voltage rectifier, 220VAC to 250VDC.
I know that the reactance of the input coil on the GSM Sniffer is almost a short circuit at lower frequencies but doesn't it pickup every radio station, television station and taxi-cab radio in town? Doesn't it also pickup mains hum and light dimmers?
Did some searching of the forum, but didn't find an answer to my question. If you used an ohm meter, and measured across a solenoid coil are you measuring the resistance of the coil or the reactance? What I want to do is calculate the inrush and holding currents of a solenoid valve in a 24V AC 60 Hz application. So if I take a measurem
I didn't except a low frequency RFID system. In this case, the situation is somewhat different. You don't have matched RF antennas rather than tuned inductive coupler coils with 125 kHz (and also mostly with 13.56 MHz RFID). To monitor system operation without disturbing the field, you can either use a very small test coil (one or a few windings
I need to wind a toroid of 330uH for the output coil of a switcher (LM2576). By formula calculator and measurement I have reached a coil design. But I have to consider saturation current also before finalizing .How to do that? Saturation flux of my ferrite material as per datasheet is 480. My inductor needs to handle 2Amps. (...)
I think, the application note answers most of your questions. I don't see the circuit as a totem-pole output. It's rather a bipolar current pulse generator with independent control timing for both drivers. The application note additionally suggests a circuit with active current limiting. But I agree, that there are some unclear points in the AN. Th
You'll find rules of thumb in RF handbooks and amateur radio literature. For complex geometries, e.g. PCB coils, I prefer a measurement or a numerical simulation. FastHenry from is a good free tool. You'll need a method to fine-tune the circuit after making it, so an oscilloscope and either a signal generator or
Seriously, the question for best method can't be answered without a full specification. An AC only measurement generally suggests a current transformer or di/dt sensing (Rogowski) coil. Both provide high bandwidth, isolation and low interference susceptibility, the latter also insensitiveness to DC currents and effectively unlimited overload ca
Hi, This measurement envyronmet called: GDO... (GridDipOscillator, & as hes name tels us, it is a very old, so ca. 80-90 years, technique) What you need: a sweeped signal generator (in your checked fequencies) with a relative small, but wideband coil as antenna, than if you are with them over your TX/RX(exactly a tuned-swinging coil) (...)
Strictly spoken, only a current transformer scales down a current. A shunt resistor in contrast converts the current to a voltage, a di/dt sensor (rogowski coil) generates a voltage proportional to the current change in time.
Your description seems to demand a constant current control loop, so you would have to provide current measurement and a PWM controller. With a contactor, the current is only limited by the "very low resistance" of the coil. Or is it just O.K. to connect the coil to a 150V supply and operate the H-bridge as solid state switch? The 50 (...)
Why don't you use a Rogowski coil to measure the current.
Hi, I am currently doing a undergraduate project in my university and need some help rgd my circuit design. I am trying to experiment with resonant inductive transfer to wirelessly transmit power. The setup is: I have a load which is an LC circuit with a capacitor connected in parallel to a copper coil. I need to drive power into this LC c
Hello, Im trying to design a circuit that would hold a small coil, about the size of a penny at 200 Celsius. Also trying to keep the size and cost way down. I believe I should be using a Thermistor but I'm not 100% sure, I checked out the temperature controlled fans but had some trouble, is it possible someone could put me in the right directi
You may want to tell about the time constant of the said capacitor-coil (LRC) circuit, but according to the switching speed of most coils, I won't expect more than a few ten or maximum one hundred ms. So obviously, the involved frequency range is much above "zero" hertz. Actually, it isn't too far apart from usually specified ESR frequency range.
At first sight, both "strange" waveforms seem to indicate RF oscillations of the power stage. This would be actually another expectable result of placing an inductive shunt into the source connection of a power stage transistor. The waveform marked as "O.K." is showing a considerable amount of negative mutual inductance. It's far from resemblin
I have the device that comes with the chips that reads and writes to the chips. In this case, you can wind of few wire turns as a montor coil, connect an oscilloscope and try to detect the carrier frequency as a first step. To identify the protocol, some deeper knowledge of RFID would be needed. You can find introducing literature a
The best way is to use larger diameter coils on both ends of the link.
Usually, a magnetic clutch is activating the compressor. It should consume a few amps. A current relay, e.g. formed by a reed contact with a coil, can be used to sense the current. Probing the switched voltage would be still the most easy way. An inductive proximity sensor has nothing to do with current measurement. As the name reveals, i
It is interesting that all analogue measurement devices are RMS value reading devices because of the working principle with a moving coil in a magnetic field.