Aleph 30 inductors

[Bassivus]

Hi,

I have ordered those copper foil inductors from ebay: 2,0mH INDUCTOR
for the aleph 30 PSU.
When I asked seller he said they are 0,3R resistance. However I measure 0,7R
Are they still good for the job or not?

[Magura]

Those are not for high power applications.

The polypropylene insulation is not to be used where things get hot.


Magura

[flg]

Originally posted by Bassivus
....When I asked seller he said they are 0,3R resistance. However I measure 0,7R
Are they still good for the job or not?

Are you using a "4 wire " measurement? To measure that low of R you need to. Not alll meters can do a 4 wire measurement. Just take your 2 wire ohm measurement between the two leads shorted together. It may be .5 ohms or something. (Ideally, yould read 0.000 ohms) You can then subtract that number from your total measurement of the inductor. It's not the most accurate but it's better than no "4 wire" capability.

[Bassivus]

Originally posted by Magura
Those are not for high power applications.

The polypropylene insulation is not to be used where things get hot.


Magura

To my knowledge polypropylene melting point is about 170°C which should be at least 100 degrees higher then acceptable coil temp. in this application. Also pp is not highly flammable and toxic. Isn't it?

[Bassivus]

Originally posted by flg

Are you using a "4 wire " measurement? To measure that low of R you need to. Not alll meters can do a 4 wire measurement. Just take your 2 wire ohm measurement between the two leads shorted together. It may be .5 ohms or something. (Ideally, yould read 0.000 ohms) You can then subtract that number from your total measurement of the inductor. It's not the most accurate but it's better than no "4 wire" capability.

Thanks,

I did not know that... I have searched about correct measuring of inductors but didn't came up with nothing clever. And like I said in earlier post I am just a non electronically educated hobbyist.

It measures 0.5R when shorted and regularly two wire measured actually flashes between 0.7 and 0.8.
So it means it IS about 0.3R.

[Zen Mod]

Originally posted by Bassivus

Thanks,

I did not know that... I have searched about correct measuring of inductors but didn't came up with nothing clever. And like I said in earlier post I am just a non electronically educated hobbyist.

It measures 0.5R when shorted and regularly two wire measured actually flashes between 0.7 and 0.8.
So it means it IS about 0.3R.

well ....... seems that you just didn't asked on right addy

I can tell ya recipe for great B-J or Aleph J chokes ;

in fact - I already wrote that recipe at least once in thread at our local forum

[Bassivus]

Originally posted by Zen Mod



well ....... seems that you just didn't asked on right addy

I can tell ya recipe for great B-J or Aleph J chokes ;

in fact - I already wrote that recipe at least once in thread at our local forum

I saw you all (back home) are busy with the new LDR passive preamp, thought I'll never get answered...

[Zen Mod]

Originally posted by Bassivus


I saw you all (back home) are busy with the new LDR passive preamp, thought I'll never get answered...

well ...... I'm always loosing that recipe , so I'm in position that I must measure dims again and again .....

try to search in Bab thread at our local forum .......

did you measure Rdc of these coils with real procedure , or with real ohmmeter , which is showing 0 when is real 0 ?

usual DVMs aren't capable of not showing/substracting usual 0,2~0,3 Ohms (measuring tips/cables/contacts) losses .

[Bassivus]

Originally posted by Zen Mod



well ...... I'm always loosing that recipe , so I'm in position that I must measure dims again and again .....

try to search in Bab thread at our local forum .......

did you measure Rdc of these coils with real procedure , or with real ohmmeter , which is showing 0 when is real 0 ?

usual DVMs aren't capable of not showing/substracting usual 0,2~0,3 Ohms (measuring tips/cables/contacts) losses .

I just checked... it does show 0,2~0,3 just touching the tips
I have searched last night but did not find it ... I'll do more thorough searching later today...

[flg]

Alternativly, you could use a small "known value" resistor? .3 ohm might be good. In series with the choke and connect them to a low voltage DC supply. 1V maybe. Measureing the votage on the resistor, divided by the R, gives you the total current and measureing the Voltage on the choke, divided by that current, gives you the DCR of the choke