Linear voltage ramp, howto?

Thread Starter

eimix

Joined Sep 2, 2008
32
I have 555(NE555N to be exactly) timer controlled via 5 pin(control voltage, if NC it has 2/3 of Vcc)
It is used for soft-start dc motor.

Now it has 220uF cap connected, but it charges fast in beginning and slow at the end. ;) yes, yes i know that all cap's does the same.

I need simple solution for slow charging in begining and fast at the end, or linear at least, is it possible without any chips?

btw, i already know about simple small current source for linear charging, but i cannot fit in my circuit. it requires external supply line, i would like to use those 2/3 of Vcc that 5th pin has.

Thanks for any comments ;)
 

Thread Starter

eimix

Joined Sep 2, 2008
32
thanks for suggestion.
but seems too complex for me right now,
i googled for such idea - but nothing simple is possible in my case :(
after some more experience in building circuit i will try this one.

thanks again
 
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