Soft Start Circuit - Too Fast Too Soon

[kptseng]

One trick you might try is to increase R1 to 560k and see if you get a second or more delay.

As drawn the circuit will work as advertised and the delay will be correct. You only need a very short delay for the transformer to build up enough flux to limit the inrush current, any longer might 'feel' and sound good but serves no purpose beyond stressing the resistor bank.

Thanks Mooly, this is a good idea, I'll probably try to get a few resistors of different value and start with 560k and go down.........

I'm really looking at 100ms to 200ms, no more.

Or 0.12sec? 120us seems awfully fast for a moving finger.

Jan

Hi Jan, my mistake for forgotten a zero behind. Should be 120ms

 

[kptseng]

Happy New Year everyone

Just a quick update: I have now replaced the initial 68kR with a 100kR 2W resistor, now the relay activation time is approx 180ms, which gives about 9 cycle.
The resistor banks temperature feels ok, not even warm.

Thank you for all the knowledge and sharing.