resistors,Bc168 replacement

[Hairy Harry]

Hi Hans

1: 1/4W or 1/8W is the power rating.  Multiply the current through
the resistor (in AMPS) by the voltage across it (in VOLTS)... thats the 
power it will dissipate (in WATTS).  Power dissipated will make the resistor 
HOT.  If you run the resistor at less than half of the rating (rule of 
thumb) it will not get uncomfortably hot.
(1/4 W size, dissipating 1/8 W = cool running)

The size of the 1/8W resistor is usually smaller than 1/4W
Watch out for the temperature that the wattage rating is specified
at... commercial parts are usually at 25C, military spec is at 70C...
so a military 1/4W part is often the size of a commercial 1/2W part.

Changing transistors depends on why the original transistor was chosen. My 
rule is that the original designers were either incredibly
stupid... or more clever than I can recognise. If they were stupid, then 
your choice of transistor may be better. If they are smarter than
you... maybe their choise is really the best one, for reasons you do not 
understand (gain, frequency range, noise, saturation voltage, thermal 
dissipation.... etc etc...).  A lot depends on the specific use.

H^) harry


>From: "Hans-H.Klos" <xmurz at gmx.de>
>To: <synth-diy at node12b53.a2000.nl>
>Subject: resistors,Bc168 replacement
>Date: Fri, 17 Nov 2000 16:12:26 +0100
>
>Hello!
>Some stupid question I have to ask:
>what is the difference between a 1/4w and a 1/8watt resistor.
>In what way does it react differently. I'm new to all this, so please
>give me some advice.
>How good is it to replace  say a BC168 by a sc2002 transistor and
>how good is repacing transistors in general (for the sound & stability)?
>Thank's for any help, I already got so much further because of this list!
>Bye
>              Hans-H.Klos

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