Can anyone suggest a good variable frequency circuit with an NE555 timer? It would ideally be possible to do on a breadboard (capacities not having a huge effect). The duty cycle needs to be close to 50%, but it doesn't have to be too exact (±10%). I know that the BJTs can lead to issues, but all I have is the NE555. I haven't really done a lot with 555s yet. I need 50kHz-1MHz, which I am going to use to drive a mosfet. The mosfet will control the primary coil of a high voltage step up transformer.
My arcs haven't been long enough with my 6V supply, nor have they been powerful enough (very difficult to light a piece of paper on fire). At higher supply voltages, it draws too much current. So I need to increase the frequency (to increase inductive reactance). I have been using an arduino, with a PWM of ~150kHz. But the mosfet already heats up a lot, despite the low switching current. It has melted a hole in my breadboard, and required a lot of heat sinking.
I think it needs more current to drive it, and a higher voltage. It also needs its capacities discharged faster. With an output of 14-15V, and up to 200mA, the NE555 seems like it will preform better than an arduino. But I am concerned about the transition. Will it be close enough to a square wave to not have the mosfet in the ohmic region for too long?
My arcs haven't been long enough with my 6V supply, nor have they been powerful enough (very difficult to light a piece of paper on fire). At higher supply voltages, it draws too much current. So I need to increase the frequency (to increase inductive reactance). I have been using an arduino, with a PWM of ~150kHz. But the mosfet already heats up a lot, despite the low switching current. It has melted a hole in my breadboard, and required a lot of heat sinking.
I think it needs more current to drive it, and a higher voltage. It also needs its capacities discharged faster. With an output of 14-15V, and up to 200mA, the NE555 seems like it will preform better than an arduino. But I am concerned about the transition. Will it be close enough to a square wave to not have the mosfet in the ohmic region for too long?