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Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am getting
wildly different figures from various sources.
Thanks all.
"StrandElectric"<Strand@dummyspit> wrote in message
news:4e004ab0$1@dnews.tpgi.com.au...
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am getting
wildly different figures from various sources.
Thanks all.
Probably quite manufacturer dependent???
Yes , depends on turns and type/length of wire included
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
Megs!"StrandElectric"
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
** The inductance is so small it is totally irrelevant compared to the 820
ohms of resistance.
.... Phil
Phil. That depends entirely on the frequency in use, in this case up to 30
**That's because there is no one, correct answer. Some wirewound resistorsCan anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
"Phil Allison" "StrandElectric"
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
** The inductance is so small it is totally irrelevant compared to the
820 ohms of resistance.
Phil. That depends entirely on the frequency in use, in this case up to 30
Megs!
** Try using this.I still neeed that measurement.
** Invariably labelled "non inductive" and cost way more.StrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound resistors
are bifilar wound,
** 10W, WW = standard rectangular cement coated resistor.You need specify which resistor you are using.
** If you speak Chinese.Better still, you should contact the manufacturer, as he/she will be able
to provide all the data you require.
** OK - you go get a 10W, 820 or 1000ohm cement resistor and YOU measureEven betterer, would be for you to measure the inductive reactance of the
resistor,
gives a reasonable result for inductance.Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am getting
wildly different figures from various sources.
Thanks all.
*if* it's a straight coil of wire with an air core, then Wheelers formula
degree of accuracy I'm aiming at.."StrandElectric"
"Phil Allison" "StrandElectric"
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
** The inductance is so small it is totally irrelevant compared to the
820 ohms of resistance.
Phil. That depends entirely on the frequency in use, in this case up to
30 Megs!
** The change in impedance is not going to be more than 2 ohms - and might
be up or down.
I still neeed that measurement.
** Try using this.
http://www.daycounter.com/Calculators/Air-Core-Inductor-Calculator.phtml
You should get about 0.3 uH
At 30 MHz, this has a Z of 56 ohms
The new impedance of your 820 ohm resistor is then 822 ohms - in theory.
You are wasting your time.
..... Phil
That's a bit hasty Phil, as you don't know what I'm trying to do and what
hoping that someone who uses Jaycar 10% R would also have a decent measuringStrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound resistors
are bifilar wound, which exhibits far lower inductance figures than
regular wound resistors. You need specify which resistor you are using.
Better still, you should contact the manufacturer, as he/she will be able
to provide all the data you require. Even betterer, would be for you to
measure the inductive reactance of the resistor, as this data is likely to
be far more useful to you.
--
Trevor Wilson
www.rageaudio.com.au
Agreed Trevor, but my crude instrument is very poor at measuring L. I was
"Trevor Wilson"
StrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound
resistors are bifilar wound,
** Invariably labelled "non inductive" and cost way more.
You need specify which resistor you are using.
** 10W, WW = standard rectangular cement coated resistor.
Better still, you should contact the manufacturer, as he/she will be able
to provide all the data you require.
** If you speak Chinese.
Even betterer, would be for you to measure the inductive reactance of the
resistor,
** OK - you go get a 10W, 820 or 1000ohm cement resistor and YOU measure
its inductance.
Go on - try !!
.... Phil
Agreed Phil!
** No it is not."Phil Allison"
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
** The inductance is so small it is totally irrelevant compared to the
820 ohms of resistance.
Phil. That depends entirely on the frequency in use, in this case up to
30 Megs!
** The change in impedance is not going to be more than 2 ohms - and
might be up or down.
I still neeed that measurement.
** Try using this.
http://www.daycounter.com/Calculators/Air-Core-Inductor-Calculator.phtml
You should get about 0.3 uH
At 30 MHz, this has a Z of 56 ohms
The new impedance of your 820 ohm resistor is then 822 ohms - in theory.
You are wasting your time.
That's a bit hasty Phil,
as you don't know what I'm trying to do
Agreed Trevor, but my crude instrument is very poor at measuring L. I was
hoping that someone who uses Jaycar 10% R would also have a decent
measuring instrument.
**I did not suggest that you try to measure inductance. I said you should"Trevor Wilson" <trevor@rageaudio.com.au> wrote in message
news:96cg0fFur4U3@mid.individual.net...
StrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound
resistors are bifilar wound, which exhibits far lower inductance
figures than regular wound resistors. You need specify which
resistor you are using. Better still, you should contact the
manufacturer, as he/she will be able to provide all the data you
require. Even betterer, would be for you to measure the inductive
reactance of the resistor, as this data is likely to be far more
useful to you. --
Trevor Wilson
www.rageaudio.com.au
Agreed Trevor, but my crude instrument is very poor at measuring L. I
was hoping that someone who uses Jaycar 10% R would also have a
decent measuring instrument.
**I said: INDUCTIVE REACTANCE."Trevor Wilson"
StrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound
resistors are bifilar wound,
** Invariably labelled "non inductive" and cost way more.
You need specify which resistor you are using.
** 10W, WW = standard rectangular cement coated resistor.
Better still, you should contact the manufacturer, as he/she will be
able to provide all the data you require.
** If you speak Chinese.
Even betterer, would be for you to measure the inductive reactance
of the resistor,
** OK - you go get a 10W, 820 or 1000ohm cement resistor and YOU
measure its inductance.
**I've done so on many occasions. Though, I hasten to add, not 820 OhmGo on - try !!
such an extreme put down! The last few posts from you have been really"StrandElectric"
"Phil Allison"
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820ohms and tell me the inductance.
** The inductance is so small it is totally irrelevant compared to the
820 ohms of resistance.
Phil. That depends entirely on the frequency in use, in this case up to
30 Megs!
** The change in impedance is not going to be more than 2 ohms - and
might be up or down.
I still neeed that measurement.
** Try using this.
http://www.daycounter.com/Calculators/Air-Core-Inductor-Calculator.phtml
You should get about 0.3 uH
At 30 MHz, this has a Z of 56 ohms
The new impedance of your 820 ohm resistor is then 822 ohms - in theory.
You are wasting your time.
That's a bit hasty Phil,
** No it is not.
as you don't know what I'm trying to do
** Not knowing what you are doing IS your problem !!
You know nothing twit.
.... Phil
Oh dear, back to type. That was a very mild comment from me hardly requiring
capacitance and seeing what frequency it resonates at?Phil Allison wrote:
"Trevor Wilson"
StrandElectric wrote:
Can anybody with a good inductance meter, please measure a 10 watt
wirewound resistor of 820oms and tell me the inductance. I am
getting wildly different figures from various sources.
**That's because there is no one, correct answer. Some wirewound
resistors are bifilar wound,
** Invariably labelled "non inductive" and cost way more.
You need specify which resistor you are using.
** 10W, WW = standard rectangular cement coated resistor.
Better still, you should contact the manufacturer, as he/she will be
able to provide all the data you require.
** If you speak Chinese.
Even betterer, would be for you to measure the inductive reactance
of the resistor,
** OK - you go get a 10W, 820 or 1000ohm cement resistor and YOU
measure its inductance.
**I said: INDUCTIVE REACTANCE.
Go on - try !!
**I've done so on many occasions. Though, I hasten to add, not 820 Ohm
resistors. Usually, much lower value resistors. The principle is the same
however. I don't see the point in trying to measure inductance directly.
As you have already stated, the resistance value will completely swap the
inductive reactance value. With rudimentary test equipment, it is simple
enough to measure the total reactance and perform the appropriate maths to
calculate inductance.
--
Trevor Wilson
www.rageaudio.com.au
Hi Trevor, I presume you mean setting up a tuned circuit with known
killfile you because you often post good sense. Could you try not to be so"StrandElectric"
Agreed Trevor, but my crude instrument is very poor at measuring L. I was
hoping that someone who uses Jaycar 10% R would also have a decent
measuring instrument.
** Calculate the impedance of 20pF of stray capacitance at 30MHz.
I'll even give you the formula:
Xc = sq. rt ( 2 . pi . F .C )
Imbecile.
.... Phil
Thanks, apart from the completely unneceassry last word. I am loath to