High speed switch

[scobby]

Hi There.

I am a bit rusty on my electronics having not touched it for 20 years.

i am looking for a switch like a solid state relay that can be triggered by say 5v and a few mA ( circuit yet to be constructed), the load will be a 12v - 5A. The tricky bit is that i need this to be done within a range of 20 khz ish more range higher would be an advantage.

Thanks in advance for any help.

 

[crutschow]

What is the nature of the load: inductance, capacitance, etc.? Does the control line need to be isolated from the load?

A power MOSFET can likely switch such a load.

 

[scobby]

I will be using two coils on the load side that will generate about 25kv. i am trying to create a high frequency spark at as i say about 20khz which i would like to adjust the hz from my pulse generator for experimentation. I was thinking of mossfet but wasn't sure if this would do it.

 

[crutschow]

Are you trying to use auto ignition coils to generate the voltage, because they typically have about a 100:1 turns ratio and thus would have 250V on the primary to generate 25kV on the secondary. And these coils are only good to about 1000Hz or so in there normal inductive flyback operating mode. You can get a higher frequency if you operate the coil with a capacitor discharge type circuit.

 

[scobby]

The answer to everything you have said is yes. Now i am lost for what to do any suggestions on how to create 25kv @ 20khz from a car battery as the source power. I have only chosen a car battery because the unit has to be mobile and its a nice readily available unit.

The project i am working on will have 25kv at each plate with an adjustable potential difference of only a few volts. I was using 2x6v coils in series hoping that the fly back would of been equal ish for crude experimentation and created the pd by means of a large resistor.

Paul