Scientech 362 Laser Power Energy Meter to Precision PSU conversion Project  - Page 1
Forum section: electronics / projects

author: denimdragon
author_rank: Regular Contributor
timestamp: September 14, 2018, 12:39:41 pm
content: I've been working with OP amps (LT1028, LT1002, OPA 27 C-DIP, OP 04 C-DIP) a lot lately and I have been using 2x 9 Volt batteries as dual pole rails to power them (Only the LT1028 so far). Since all of these are "low" noise, I know that I needed a low noise power source, and batteries are pretty good low noise DC sources, but they are limited in many areas, especially in the amount of voltage they put out.Initially, I was going to build a linear PSU and use it (I still will later because I have a ton of massive transformers grabbed from Pioneer, and Onkyo audio equipment), but once I looked at the schematic on this Scientech 362 Power Energy Meter, I came up with this idea to re-purpose it to use for my OP amp projects. It's already configured with ±15V and a -4V rail.Why reinvent the wheel? Not to mention I need this for school as soon as possible.I am green at all this. I'm pretty good with repairs but I haven't built a complex system (relative term of course), so as usual, I've come seeking aid from the experts. Note that the 362 was working perfectly before I disassembled it.Now here are a few of my ideas of what my target goal is and some ideas/concerns I have about reaching this goal:Requirements:The most important thing here, obviously, is low noise output (given what I have to work with - List below)I would like to be able to adjust the voltages pretty accuratelyIn the future, I would also like to use it to power my Vref builds I've been playing with.It must be done with what I have on hand.Ideas and Concerns:I have read that a Vref can be used as a voltage regulator (more like a filter). I want to apply it in this project. How would I go about it?I've looked at some of Dave's videos on noise measurements and I'm wondering what would be my best approach. (see below)Since this unit wasn't made for this purpose, will I need to add EMI shielding?List of components on hand:.01, .1, .25, .5% resistors (max 25ppm TC) high and low values (Can I run them in series to get the needed values I may be missing, and will the TC be summed?)OP Amps (listed above and some jelly beans)Vrefs LT1021BMH-5, LT1021CIN8-10, LM399AH (Aged), LM199AH (Aged), Ref01.Capacitors (quite a few)Voltage regulators 78xx, 79xx, 337, 317TI bus load of donor boards from various equipment-Mostly audio and test equipment but some computer stuff alsoI have a HP3456A, 3457A, Tek 784D, Rigol DS1054, Goldstar 20MHz CRO, 2 PSUs (Tek 282, BK 1785B), and 2 LCR meters (DE5000, BK878) HP8657B, and a couple of FunGens 5MHz, 3MHz.I'm not sure if the sig gens and other stuff will help with testing, but I'm just attempting to paint a clear picture of what's available. Any help would be greatly appreciated.Note: The PDF is the schematic for the 362

author: LaserSteve
author_rank: Super Contributor
timestamp: September 14, 2018, 04:48:38 pm
content: How about telling everyone this is a Laser Power/Energy meter. The laser beam is detected with a custom Peltier array with a energy absorber bonded to one side and a heat sink to the other.Steve

author: denimdragon
author_rank: Regular Contributor
timestamp: September 14, 2018, 09:03:55 pm
content: Quote from: LaserSteve on September 14, 2018, 04:48:38 pmPardon the lack of totally info. I will, however say that it attracted an expert on the subject "LaserSteve"Very cool construction and I love the enclosure on it. Truly a well built piece of equipment which is one of the reason I wanted to use it for my first mod. Thanks again for your input.