what you say all makes sense, and thanks
would you recomend using a trimming cap aswell?, or do I put the cap in, then adjust the pot to compentsate for the incaccuracy? I will prob use two preset pots for the resistors, and a multimeter to make sure of them...
p.s. you don't happen to know the exact values of the resistor and the cap to make 100hz...?, or how i can work them out.
the pic below shows the type of astable i am using. I reckon that if Ra=7K, and Rb=150K, and C=47nF, I will get 100.01Hz..., which is prob near enough, but i'm not sure what accuracy that will give, after, say, 10secs? ahhhh brain ache. School maths lessons should teach us stuff like this, its much more useful
**broken link removed**
Thanks everyone, i'm not sure what i'd do without u