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1

A Helmholtz coil would require a current source rather than voltage source. The output voltage of the audio amplifier is proportional to the signal input voltage. What you would need is an amplifier whom output current is proportional to the input voltage - voltage controlled current source. This can be done with an operational amplifier, but you should know ...


2

I've seen this question before... It depends how much your coil looks like a loudspeaker. If its DC resistance is above a few ohms, then it's a reasonable approximation of a 4 ohms loudspeaker, whose DC resistance is usually around 3 ohms. In this case an audio amp rated for 4 ohms will work fine. You can use an audio amp from the pawn shop, or a kit from ...


1

It's easy enough provided the two items can be matched up. Obviously, you need an amp that goes down to 10 Hz. Not many audio amps do that, so check the specs very carefully. More technically, the output of the generator must also be electrically matched to the input of the amp. For example the amp may have an impedance of 1 kΩ and require an input of 100 mV ...


2

The Q is given by the parallel resistance of the coil. so simply add a much larger high quality foil cap in parallel to the coil to bring down it's resonance frequency to a measurable range. And determine the impedance at resonance.


1

Best way to measure Q of very high Q coils is to use the venerable Q Meter. Two typicl examples come to mind, the Boonton 260 which is a late 1950's box or the HP4242A. Both use high impedance voltmeters. You simply place the inductor across the terminals and tune the internal variable cap until the meter peaks, then direct read from the meter the Q. The ...


5

Well, I will try to translate this Russian text at least to justify my Slavic name Cyril:) By the way, Russian is very close to my Bulgarian. Тисо-Продакшин is Tiso-Production - maybe the producer EМ-87 - I don't know what it is... maybe 87 is the year Rобм is Rcoil ("обмотка" is "coil"), i.e. this is the coil resistance = 23 Ohm W = ...


0

Turns out the tip31c was burned, and the primary was shorting to the secondary.


1

Non-latching Normally Open relay. But relays are assumed to be non-latching unless latching is specified.


2

It's either a transformer or common-mode choke. Try putting the shield part back on and see if the panel will work again. If so, some glue and you'd be good to go.


1

The circuit in the image you provide is probably not what you want. Consider the wires connected to the AC voltage labeled "-". One wire goes through a node labeled "Main Panel G+N", to a node labeled "Main Panel Earth", to a node labeled "Vehicle chassis ground", then to the relay contact labeled R2. Going in the ...


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