Hi,

I need to buy or build an intensity control for an old Synrad laser.

Synrad no longer have parts or schematics and the RF supply is all built into the sealed enclosure. Synrad assures me that their UC-1000 or UC-2000 will drive it but I cannot spring for the thousand-bucks.

From the UC-2000 manual, I need a PWM at 5KHz at 5v and output current 100mA MAX through a 50 Ohm CMOS circuit, whatever that means.

Any suggestions please? I have looked at some PWM DC-motor controls but they are all low frequency around 500Hz etc.

Thanks in advance.

Dave

Google "555 timer" and you'll find a boatload of applicable circuits that will cost you $5 to build. They may not have the computer control offered by the UC-x000, but it will get you started. The fact that you didn't understand any of the jargon they mentioned, though, says you should have a local high schooler fluent in electronics purchase the correct components and build it for you.

Google "555 timer" and you'll find a boatload of applicable circuits that will cost you $5 to build.

Thanks I had already done that, but have not been able to figure out how to get the 5KHz frequency I need, most operate around 500Hz. I have not quit yet.

Dave

The circuit's frequency is dependant upon the component values chosen... there's an equation that relates component values to frequency, so plug in the frequency you need and work backwards using reasonable component values. There are even online Java tables that will do this calculation for you. 5kHz is no problem for a 555 circuit.

I think you can even generate the signal via Mach3 and the parallel port...but if not, it is easy enough to program the simplest 8 bit microcontroller, such as a pic or atmel to do the job and more. That is what I did.