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Holt's Achievements


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  1. 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]
  2. 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?
  3. http://www.electronics-lab.com/projects/power/010/index.html Has anyone build this? comments much appreciated Holt
  4. 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 ?
  5. 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
  6. 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?
  7. Have a look at page 30 for links to the newest designs
  8. Hi davenz At page 30 you will find this. http://www.electronics-lab.com/forum/index.php?topic=19066.msg91051#msg91051
  9. 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
  10. 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
  11. 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
  12. 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
  13. It was supposed to adjust 0 volt Holt
  14. I use the TLE2141, R10 = 1Kohm, trimpot = 5Kohm Holt
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