# Induction Heater L and C choice

#### ElectroNoob2021

Joined Oct 28, 2021
4
Hello guys,

I am trying to build an induction heater but i am confused beacause whenever i find an article about it there is no source that says how i am supposed to pick the L or C for it.

I found that i can calculate the resonant frequency from the formula f=1/2π*sqrtLC but i don't know the frequency either.

So i was wondering if i just pick a frequency and from how many hz to how many hz and then calculate the L C or i have a big gap in my knowledge somewhere because i cannot understand how to find this.

Thanks for the help in advance.

#### ElectroNoob2021

Joined Oct 28, 2021
4
Well just small metals and stuff like that for starters then i will go to something larger.

This guy is heating and melting stuff that i would too but i want to heat up even smaller ones.

Also i want to understand how to calculate this as well not just copy his work.

Thanks again.

Last edited:

#### ElectroNoob2021

Joined Oct 28, 2021
4
What do you intend heating and how large/mass does it have? This is one criteria for picking the frequency

500W https://markobakula.wordpress.com/power-electronics/500w-royer-induction-heater/

Well just small metals and stuff like that for starters then i will go to something larger.

This guy is heating and melting stuff that i would too but i want to heat up even smaller ones.

Also i want to understand how to calculate this as well not just copy his work.

Thanks again.

Joined Jul 18, 2013
28,522
Going by the industrial ones I have worked with went from large 70Kg iron plates using the mains frequency to silver solder joint for 14g steel using a single turn coil at 450Khz.
For different temperatures with the same coil, the power ON time is controlled to suit.

#### ElectroNoob2021

Joined Oct 28, 2021
4
So it was depending on the duty cycle for the heat