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Mouser, The first thing you need to do is find out where you are on the impedance curve. around tuning you will need a scope to look at the phase relationship between current and voltage. I have no idea whether the load is more capacitive or inductive at that point.
You are very likely on the second impedance rise on the side closest to tuning. this side is inductive and reaches its most inductive point about half way up the curve. If you are anywhere on this side of the curve you can do some correction with a series cap, (passive subsonic filter). just try experimenting. You can start by calculating the impedance of a cap at your frequency that sould be equal to around the impedance of the inductance at that point. you need a good clamp-on to see how much your changing the current though. a SPL meter would work also. In any case a scope would be very usefull. you could design something to correct the power factor much greater. good luck. sorry if I worded anything wrong, its early and I just woke up. I'll read this later.
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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It looks similar to that if you have the equipment on a scope.
I can get a scope, I just needed some information as to how to measure high amperage using one.
My idea was (as I only need phase) to wrap a wire around the speaker wire and pick up the induced noise as the current, but I don't know how the phase of this setup would affect it (or would it be in phase with the current in the wire?)
Then use the voltage setting on the other channel of the oscilloscope. Then use a DMM on amperage mode to measure actual current draw, or a clamp on ammeter if I can get one.
y main point is can I just wrap some wires around it as a probe, or do I need to do something else, and what problems might be encountered.
Mr. Dank, It's Colin here, I just changed my display name to the one I use on some other forums.
-------------------- *hmm need to think of a new sig*
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ahh a name change ehh. colin, You could try the wire wrap thing with a resistor, that way you could align the current and voltage on the scope then switch to the speaker. Normally, you would use a clamp on device that outputs voltage to measure current. I dont know how much they cost or where you get them, but they have them for scopes.
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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posted
Dont use a light bulb! they are purely resistive but change resistance as they heat up. Thats why they blow when you turn them on, the resistance is lowest when the coils are cold.
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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posted
if you want to measure amp draw, all you need is a good multimeter with a clip-on current adapter(40 quid or so) I think Halford's has one, but I'm not sure. Maybe HomeBase? I don't know, it's hard to find stuff in the UK.
goodluck
-------------------- Life is the study of dying- how to do it right
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phase plots are kinda weird to interpret. I'd recommend reading up on it first. The phase plot will look something like / or O or \ or an ellipse.
Posts: 768 | From: Ottawa, On, Canada | Registered: May 2000
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