Induction heater

Poor little mosfet. Max. Current seems to be more like 290A and frequency at roughly 4.8 Mhz.

4.810Mhz to be more precise. Also R1 and R2 of the 555 timer should not be lower than 1k ohm.

Manufacturer recommends a minimum of 1k for the timing resistors.

@BillyT probably for good reasons tho :)

@ViolationMad, start at the induction coil how does it look like and what inductance you gues it will have. From my experience it will have an inducrivity of about 10uH or smaller, but 80nH is just a few or maybe just 10cm of wire which will be hard to wind a plante as coil. The frequency depends on the use material mainly you would like to heatup. Nails, screws, motor block parts or a cooking pot in your kitchen? Range will be 30kHz to maybe upto 300kHz in modern cases. Most work at 30-50kHz. But MHz is quite to high. So start to construct something with 10uH and calculate capacitors for 40kHz and you will see how much current you can pump into this resonator, which is actually the main secret to have a strong magnetic field with many VA to heatup your soup!

play with this more realistic setup, if you have no IRF540, but still have as i remember IRLB3034 you can do the relevant Rdson setup with the top right little helper circuit http://everycircuit.com/circuit/5397514995105792

uuups i saw Voltransistor close to the headline and later on i start the comment i saw ViolationMad and mixed owner and commentator, sorry. But in case ViolationMad you might like to rebuild this circuit 😉

@hurz Haha no worries. And since you gave such an detailed explanation I'm actually considering rebuilding it but with a different source of the PWM signal (I'm thinking of advanced logic for fast on and off switching) ;). It probably will have to wait a bit though cause I'm bothered about a stable supply for tubes at the moment.

problem with such timing is frequency controll the correct positions of on and off in timing while the frequency does change for differnet loads and different power levels, all this in combination makes to controll unit a little complicated when you want the maximum out of it