[sdiy] capacitor ID

[Tony Clark]

> - i believe i have the pins of the lm741 'split' like the normal ic. where's
> pin 1 on the ic version though? i've used sockets for the ic's. so i should
> just be able to stick it in like a normal ic, right?

   Look for the notch on one end of the IC.  Pin one is always the first 
pin on the left side.

> -there's another thing that still confuses me. resistors. even with the
> excellent graphic resistor calculator
> http://www.dannyg.com/javascript/res2/resistor.htm all this goed from a
> resistor having 3 bands and a tolerance band. many i see, however, have more
> than one. how should that be counted?

   All resistors have Value-Multiplier-Tolerance bands, the only 
difference is how many Value bands there are.  For 5-10% resistors, there 
are 2 value bands, 1 multiplier, and 1 tolerance.  For 1% resistors, 
there are _3_ value bands, 1 multiplier and 1 tolerance.
   So a 1K resistor should look like this:

      Value     Multiplier Tolerance
   Brown-Black -   Red    - (silver/gold/etc) for 5-10%
        10     x  10^2    - tolerance

         Value        Multiplier Tolerance
   Brown-Black-Black -  Brown   - Brown for 1%
         100         x  10^1    - tolerance

   Using brown for the tolerance for a 1% was a bad choice as you might 
be tempted to read the value backwards.  IE 1K 1% backwards would be 
brown-brown-black-black-brown which would read 110 ohms, and since there 
actually IS a 110 ohm resistor, the only way to really tell is to 
actually measure it!  Fortunately if you _knew_ you hadn't bought any 110 
ohm resistors, then it's a bit easier to tell what it is...  :)

> anyway, today the lm741 will go in and then.. either 'boom' (i took care to
> watch the caps' polarity), 'nothing' or 'another usable analogue synth!'..

   Before you power the circuit up, it is always a good idea to use a 
multi-meter to make sure that there are no "shorts" on the power lines.  
Use the lowest resistance setting on your DMM and check the positive and 
negative lines in respect to ground.  If the audible alarm goes off (or 
the reading shows something close to 0), you might want to re-examine 
everything!

   Good luck!

   Tony

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