Holt

Hello everyone I am in the machine buisness, and have my own old lathe in my little hobby workshop, i scored a Heidenhain glass scale at work, i want to use for digital readout of position, i have a program on the PC, but it only handles 0-5V TTL signals, and the scale put out sine wave. I have been searching the net, but only found out i should use a Schmitt trigger to avoid noise. I am not able to develop schematics, but i can build it if someone have the schematics. Here is a scan of the sine wave from the Heidenhain mounting instructions And here is what the output should look like [img width=680 height=510]

My transformer is 18.5v (X2) 3.5A, would it OK if i don't go below 5 or 6V, and use a significant larger heatsink and capacitor?

http://www.electronics-lab.com/projects/power/010/index.html Has anyone build this? comments much appreciated Holt

Thank you very much for your help! I have now been measuring all transistors in the circuit, and they seem to be okay, but there are two thyristors in the circuit, a BRX46 and a BRX53, are there any way to measure if they are OK ?

I took your advice and measured it with a diode tester, and i measure something from base to emitter/collector when i connect neg to base, but nothing when i connect pos to base. shouldn't it be emitter in one direction and collector in the other direction (sorry if i am a bit vague, but English isn't my native languish ) PS: it could be diffcult to find a replacement, this transistor are according to the datasheed especially made for flash control

My trusted old Braun BVC 370 Hammerhead flash have been playing tricks on me, it fires all its charge at once instead of adjusting the output. while measuring various components, i discovered that there were no connection between base and emitter/collector on a BD287 PNP transistor even with the meter at 2Mohm. I was happy, i had found the error! Well i didn't stay happy very long, i can find tons of datasheets, but not a single shop selling the damn thing, Can anyone help me please?

Have a look at page 30 for links to the newest designs

Hi davenz At page 30 you will find this. http://www.electronics-lab.com/forum/index.php?topic=19066.msg91051#msg91051

The newest schematics and parts list must be this one (Dec 09) http://www.electronics-lab.com/forum/index.php?topic=19066.msg87803#msg87803 The newest pcb design must be tesseract

If you look in the parts list in the first post at page 1 you can see 3 types of transistors suggestet, and that the resistors should be in the area of 0,33 ohm, two transistors for 3A and three transistors for 5A http://www.electronics-lab.com/forum/index.php?topic=19066.msg87803#msg87803

If you look at Tesseract

you could easily get rid of one of the wires if you rotate D9 90 deg, and move a couple of tracs a bit Holt a bit like this, but i couldent rotate D930V_PSU_rev.zip

You can get them here: http://de.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6612000 or you can order samples from TEXAS INSTRUMENTS like i did, ordered them sunday and got them tuesday- pretty fast from USA to Denmark. I dont know if it is possibel to buy from RS in Germany unless you are a registret compagny, it isent in Denmark, thats why i orderet the samples If only you had postet the PCB design 2 weeks before, it was just what i was looking for, its looking really good :D Holt

It was supposed to adjust 0 volt Holt

I use the TLE2141, R10 = 1Kohm, trimpot = 5Kohm Holt

Well- i have made a small test, and it seems to work, the only thing not working is RV1 who has no effect at all, not that it matters, the voltage is 0 when turned down, but no adjustment possibel. i have measuret the voltage on pin 1 and pin 5 on U2, and it dosent vary when adjusting RV1. It seems that the voltage is occilating a bit, but it can be my voltmeter playing tricks on me. I will put it all together in the cabinet and make some more tests Holt

You should be aware of the footprints of some of the capacitors and the trimpots, i am using an offprint bridge rectifier, because i am going for the 5A version, and i had an 35A rectifier, perhaps a little overkill, but i had it. i havent finished the psu yet, but should be able to do a test in a couple of days, i am mounting Q2 offprint aswell, i have made the cabinet of aluminium, so i will just mount it at the bottom plate Holt

Thanks redwire, here we go, not quite professional, but i am new to eagle EDIT: be aware that one of the LED connections are a via point, if you dont mount both LEDs you should solder a piece of wire in the via point PS-6.pdf PS-6_bund.pdf PS-6_top.pdf

I have just finished a double sidet pcb using the scematics from redwire, i have modifiet it a little, making the routes and soldering points a little wider to make it a bit more DIY friently, i used the laser print transfer metod from this link http://www.riccibitti.com/pcb/pcb.htm its a bit of a PITA to solder ic-sockets and some of the other components without "eyelet"connector pipes. i have the scematics on a PDF file (front, back and components) but i dont know how to upload them to the site Holt

Does anyone have a single side pcb layout they wish to share on this site? Holt