[AMPS] More amplifier experiments

[Tom Rauch]

> Date:          Wed, 27 May 1998 10:36:12 -0400 (EDT)
> From:          km1h@juno.com
> Subject:       Re: [AMPS] More amplifier experiments
> To:            amps@contesting.com

> I seem to recollect suggesting the new 5W metal oxide resistors from
> Mouser more than once Jon. 
> They are cheap and you can buy several values to experiment. 
> Are they inductive....not that I can measure on either a hand held LCR
> meter or an old Tektronix 130 LC Meter. My HP-4271B has died. In any
> event they seem to function fine in suppressor circuits up thru 50MHz.

The 5 watt metal oxide resistors I have sampled from Mouser are very 
inductive. Not only that, you have NO control over who's resistors 
they send you.

If anyone knows of a non-inductive 5 watt standard off the shelf 
resistor let me know....I've been looking for one for years.
  
> And...yes, not all 2W "carbons" are non-inductive. I bought several that
> went bang on me. Turns out they used what appears to be resistance wire
> wrapped around a small carbon core. The only true carbons that I know of
> are the Allen-Bradley ones that carry the Mil-Spec designation.

The keyword is "composition" type carbons. Carbon films and 
conventional  carbons use a carbon coating on a ceramic element, with 
the carbon cut into a spiral.

Metal oxides and metal films are the manufactured same way except the 
film is metallic. 

Cut one open and look at it.    

73, Tom W8JI
w8ji.tom@MCIONE.com

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