Hi,
I'm new to this lectronics and now I know why I failed to understand physics.
I want to build an astable 555 timer circuit. I read a lot of info on the web in various forms and found two formulae for working out the capacitor and resistor values. But it doesn't make sense!
Tspace = 0.7R2C
which I assume is Tspace = 0.7 x R2 x C
The next formula to get R2 (as I know Tspace is 1s) and the C(apacitor) is guessed at 10uF:
R2 = 1/(0.7 x 10)
The result they give is 143K resistor. But 1/(0.7 x 10) is 0.14285 (0.143)
So I got my 143 but it's a fraction not in the thousands.
What did I miss PLEASE?
I'm new to this lectronics and now I know why I failed to understand physics.
I want to build an astable 555 timer circuit. I read a lot of info on the web in various forms and found two formulae for working out the capacitor and resistor values. But it doesn't make sense!
Tspace = 0.7R2C
which I assume is Tspace = 0.7 x R2 x C
The next formula to get R2 (as I know Tspace is 1s) and the C(apacitor) is guessed at 10uF:
R2 = 1/(0.7 x 10)
The result they give is 143K resistor. But 1/(0.7 x 10) is 0.14285 (0.143)
So I got my 143 but it's a fraction not in the thousands.
What did I miss PLEASE?