[sdiy] LAG circuit de-tuning VCO question

[Neil Johnson]

Hi Dave,

> I swapped out the aluminium electrolytic for a wima poly cap of 680nF,
> and a 1uF poly box cap (rapid own brand) and both worked fine - no problem!
> I would never have suspected the difference would be so dramatic -
> either alu electros are simply not good enough, or maybe I have a bad
> batch...

Well yes leakage for an aluminium electrolytic is typically quite high. 
  For example, looking at a basic aluminium electrolytic from Rapid 
(part 11-3680) the leakage current is specified at max.3uA.

3uA through 1M0 is 3V.

Neil
-- 
www.njohnson.co.uk