Please help me identify these components! - Page 1
Forum section: electronics / beginners

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: January 09, 2020, 01:48:25 am
content: Hey there, so I’m not good with lasers and tube technology as of yet, but these look like lasers. They have a manufacture date code of January 1992. The numbers that stand out the most to me is LGR 7655. I looked it up and found lasers, but they were a totally different construction and date. Can someone help me identify the details of these components? A data sheet would be fantastic! Google is currently failing me.Thank you!Also, I held them so you could get an idea of the size.

author: StillTrying
author_rank: Super Contributor
timestamp: January 09, 2020, 02:04:45 am
content: Neon Helium Lasers according to the tech site ebay.

author: james_s
author_rank: Super Contributor
timestamp: January 09, 2020, 02:04:57 am
content: Those are helium-neon laser tubes, almost certainly the common 632.8nm red at about 0.5mW in good health. Small tubes like those were commonly used in handheld barcode scanners back before visible diode lasers became available.They have some value to the right person, a direct emission diode can't touch the beam quality or wavelength stability of a gas laser.

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: January 09, 2020, 04:13:40 am
content: Quote from: james_s on January 09, 2020, 02:04:57 amHm, quite interesting. I’ll need to see if I can get a proper driver for it. I think I know where to acquire them, but just in case, anyone is welcome to post links to listings of driver boards for this laser tube.Also... .5mW? These have .64 and .65 mW written directly on them!

author: james_s
author_rank: Super Contributor
timestamp: January 09, 2020, 05:38:11 am
content: The power supplies are usually potted bricks, for small tubes like that the voltage will be around 1200V at a few mA. Those labels certainly suggest that was the measured power at some point. Sam's laser FAQ is a goldmine of information.https://www.repairfaq.org/sam/lasersam.htm

author: Gyro
author_rank: Super Contributor
timestamp: January 09, 2020, 10:22:03 am
content: Quote from: WyverntekGameRepairs on January 09, 2020, 04:13:40 amThey are 0.5mW nominal. The figures written on them are what they actually achieved on test. There are manufacturing variances and the light output will drop over the life of the tubes.The power supply needs to supply around [Edit: several kV] at a few uA for the tubes to 'strike', they then drop to a lower operating voltage at the rated current when running. (just like neon bulbs but at a higher voltage). This is often achieved with a voltage multiplier where the capacitors in the later stages are too low in value to maintain the high voltage at running current.Laser tubes also require a ballast resistor very close to the Anode (within about 50mm) to operate correctly, they are often built into the tube housing but with bare tubes, you need to provide it.P.S. The datasheet is pretty easy to find on the web, here's the manufacturer page:https://www.lambdaphoto.co.uk/lasos-lgr-7655-he-ne-laser-tube.htmland I've attached the datasheet below (it's a 0.6mW tube).