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Astable circuit movement? Answered

hi

im using the circuit and the calculator in this link
it works fine , but the movement from (low) to (high) goes very fast and sudden , and so the movement from low to high .
what i want is gradual (ascending) increase from low to high , like 4 seconds or something , then sudden decrease to low , then gradual increase to high again , and so on
what changes should i do , or what circuit should i use ?

any links or information would be helpful

thank you  :)

Tags:astable

Discussions

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0
ARJOON
ARJOON

9 years ago

sawtooth wave

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frollard
frollard

9 years ago

put a massive capacitor on the output to make it slowly come on.

You'll need to switch power to the capacitor AND after the capacitor to the load so it shuts of suddenly, rather than fading back out

You'll need a parasitic drain resistor to discharge the capacitor while its disconnected from power.

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steveastrouk
steveastrouk

Answer 9 years ago

Won't work. Capacitor will be a short circuit when its discharged and a low impedance source when its fully charged, so it bye-bye output transistors.

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steveastrouk
steveastrouk

9 years ago

Look at the voltage on the timing capacitor, and don't put much load on it.

Steve