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Pain relief unit

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beaty40

New Member
Hi,

I have been experimenting with a pain relief unit working on producing similar results to a TENs unit. One of the drawbacks with a TENs unitis that it produces a more or less continuous output.

The signal for my unit is provided from a pre-recorded wave fed into a battery power amp. The output from the amp then goes through a reversed audio output transformer[RS 273-1380] to two TENs pads. The amp is protected by a 4 ohm resistor between the amp and the transformer.

Unfortunately the transformer soon saturates. Is there a simple way to prevent this from happening? A typical load is assumed to be about 500ohms.

Beaty
 

Chippie

Member
Transcutaneous Electrical Nerve Stimulation........... 8)

quite good if you're into masochism....... :lol: I tried one from my local GP's surgery for my back some time ago.......not very effective imho, it just gives you something else to think about....
 

bogdanfirst

New Member
maybe you can connect the transformer trough a capacitor? i assume that the transformer is not very close to 500R. but if you got so much up to 500R why did you connect it trough a 4R resistor?
you can put a resistor in series with it with the value equal with the diference between 500ohms and the transformer resitance.
 

beaty40

New Member
Hi,

The idea of the 4ohm resistor, in series, was to prevent oscillation in the amp. The 500 ohm load is a theoretical figure[used in TENs literature] to denote the resistance of the body. I think it is fair to assume that this will not be constant.

Beaty
 

bogdanfirst

New Member
if you say the resitance of the skin is 500R i don't believe it. even if the electrodes are quite near each other, the resistance will be a few 10's or 100's of KiloOhms.
now about your amp....
oyu say the transformer gets saturated....try to
reduce the amplitude or the volume of the signal that gets into the amp....
or try to increase the load resitance, use another transformer, or use a larver value reistancein place of the 4 ohm.
 

beaty40

New Member
Hi,

I have also tried a different transformer[RS 32-1031] which is a 70V line transformer. But it does not stop the saturation. The characteristic appear to be OK though.

I thought the problem was battery drain at first but switching off the system and then restarting cure it for a short while.

Beaty
 

Nostrafus

New Member
Yeah, I'd say just get a back massager, and a couple of magnets, it'll probably work better, and do less damage to your body. Unless of course you're into cutting.
 
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