Hi,
I have a HeNe gas laser and high voltage driver. I've had it for about 10 years and it's now stopped working properly - the output has become pulsed rather than continuous. It's a rather fast pulse, you can't detect it just looking at it but if you move the beam it creates a series of spots. I think the capacitors in the driver are failing and it's not smoothing the input AC power any more.
I'm thinking of putting a capacitor in parallel with the driver to smooth the output. There is already a current limiting resistor in series with the laser tube so I hope the driver is still providing enough peak power to charge the cap and power the laser.
The driver's rated output is 2300V dc at 6.5mA (from a 220V AC input). I've worked out providing 6.5mA for 1/50th second at 2300V would require a 56.5nF capacitor. My local electronics supplier has 22nF, 3kV ceramic capacitors so three of these should provide enough smoothing.
My question: Do you think this is a resonable assumption of the cause of the problem and is the solution viable?
Should I dissasemble the HV driver and try to fix the components in it rather than working around the problem with an external solutiuon?
I don't know the working's of the driver, not even if it is switchmode or purely transformer based. It's just a sealed black tube.
ps, I don't have much experience of circuits at these voltages, but I am aware of the dangers, especially when combined with capacitors or DC supplies which probably contain caps.
I have a HeNe gas laser and high voltage driver. I've had it for about 10 years and it's now stopped working properly - the output has become pulsed rather than continuous. It's a rather fast pulse, you can't detect it just looking at it but if you move the beam it creates a series of spots. I think the capacitors in the driver are failing and it's not smoothing the input AC power any more.
I'm thinking of putting a capacitor in parallel with the driver to smooth the output. There is already a current limiting resistor in series with the laser tube so I hope the driver is still providing enough peak power to charge the cap and power the laser.
The driver's rated output is 2300V dc at 6.5mA (from a 220V AC input). I've worked out providing 6.5mA for 1/50th second at 2300V would require a 56.5nF capacitor. My local electronics supplier has 22nF, 3kV ceramic capacitors so three of these should provide enough smoothing.
My question: Do you think this is a resonable assumption of the cause of the problem and is the solution viable?
Should I dissasemble the HV driver and try to fix the components in it rather than working around the problem with an external solutiuon?
I don't know the working's of the driver, not even if it is switchmode or purely transformer based. It's just a sealed black tube.
ps, I don't have much experience of circuits at these voltages, but I am aware of the dangers, especially when combined with capacitors or DC supplies which probably contain caps.