Delay on-instant off with 555 timer

[eccerr0r]

Re: Delay on-instant off with 555 timer

Ideally the inrush NTC/PTC thermistors run on their own without the need for the shunting relay.

Both will work if the expected operating temperature is where you expect the circuit to run.

NTC gets hot and stays hot during operation, keeping its resistance low.

PTC due to the inrush will get hot really fast, then the resistance goes up fast, limiting current. However then current goes down when the inrush is over, the PTC cools down, and resistance drops back low to a low dissipation number.

Weird that both actually work if they are designed properly.

[budm]

Re: Delay on-instant off with 555 timer

Since you are going to bypass the NTC with relay, then you can use resistor in place of NTC.

[Dannyx]

Re: Delay on-instant off with 555 timer

That's precisely why I went with resistors from the start

Also, I just noticed Redwire calculated the cap energy for 20000uF. Each transformer+rectifier gets a single 10000uF cap in my case, so the energy is even less than that. Of course, I COULD add a second one, for 20000uF after all....