: Hello, : I would like to build the above mentioned power supply but am only : familiar with linear power supply theory. Any ideas or schematics would : be greatly appreciated. The DC to DC convertors that used to run these : tubes were rated at 1kV @ 3-4ma output but there was no information : mentioned on a striking voltage. I would like to power it with the 110VAC : line. I built a linear supply for a HeNe tube which requires 2400V @6.5mA with a striking voltage of about 5Kv. You can bet the stiking voltage for a 1kV tube is over 2KV easily. I chose a linear supply to reduce the noise in the laser light that can be a byproduct of a cheap switch mode supply - plus this was years ago and switchmode was not as prevalent. The supply was a neon light transformer feeding a normal bridge rectifier with filter caps, followed by a series pass current regulator. It is easy to burn out or greatly reduce the life of many HeNe tubes by pushing too much current through them - so the current limiting aspect of the supply was important. The striking voltage was obtained by wiring a very low current voltage tripler around the main supply. Some items which made the supply tough to design: o finding a neon xformer with an output close to 2400V o finding good quality filter caps which could be stacked to withstand 2800-3000v. o finding good quality rectifiers and caps which could withstand the full 6KV open circuit striking voltage. o designing a current regulator which would pass precisely 6.5mA with low noise, and over a voltage differential of 200-800V (the worst case difference between the highest transformer output voltage at high line voltage and the lowest HeNe tube operating voltage, and vice-versa). The supply is heavy, and the parts are hard to obtain. If I did it over now - I'd take the time to design a switch mode supply. Jim D.
Date: 17 May 1996 21:11:32 GMT
Original Subject: Re: Need He-Ne laser pwr supply ideas