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  1. CDRIVE

    LED Signal Dummy load

    Well even in the LED circuit in post #1 I see 4 switches that I believe was explained as relay contacts or load terminals of SSR's. So regardless of whether the signal head uses incandescent or LED lamps I think I'm doomed to a perpetual state of confusion. I simply don't see the need for more...
  2. CDRIVE

    LED Signal Dummy load

    So we're back to square one again and I can't fathom the need for 4 dummy load/Indicator circuits because the dummy loads can't be used on the output side of the LED array relay contacts (ER1 through ER4) without closing the relay contacts or jumping them. Either way it will defeat the purpose...
  3. CDRIVE

    Information for a complete beginner

    Dear Mr. Skywalker, may I suggest the you check out Ebay. You can buy the boards with a remote included cheaper than you could ever build it...
  4. CDRIVE

    LED Signal Dummy load

    This schematic seems to indicate that each LED array is switched ON/OFF in the 12V side of the transformer through ER-1 to ER-4. In this case the LED array currents are reflected back to the ECR (110VAC Primary) side of the transformer. If your goal is to provide a dummy load on the secondary...
  5. CDRIVE

    Pin 7 of 555 timer doesn't discharge

    No, I don't charge for anything. Here's the link to the Picaxe home page. http://www.picaxe.com/ Here's the link to the Picaxe 08M2 8pin DIP. http://www.picaxe.com/Hardware/PICAXE-Chips/PICAXE-08M2-microcontroller Here's the link to download the FREE software.. http://www.picaxe.com/Software If...
  6. CDRIVE

    Pin 7 of 555 timer doesn't discharge

    If you go with Picaxe I'll design the circuit and write the code for you. ;) Picaxe will open a whole new world to you! Chris
  7. CDRIVE

    LED Signal Dummy load

    In the event that you would like more LED's for aesthetics you can incorporate add quite a few as shown in this modified schematic. I show only three LED's but you can add more by just repeated parallel resistor and series LED as shown. I'm curious... Does the signal head incorporate an...
  8. CDRIVE

    LED Signal Dummy load

    Herschel, I just wanted you to know that this didn't go unnoticed. Agreed, except for SSR's which can be designed to draw just about zilch. ;) On that note he can't use just a switch because his coil Ω is only ~ 30Ω which would pull about 3.7A @ 110VAC. Chris
  9. CDRIVE

    LED Signal Dummy load

    This is what Steve and I are describing. Now let's talk about this statement... You're confusing me again. Your schematic indicates only 1 current sensing relay in series with paralleled LED strings. Your schematic also indicates that each of those LED strings are activated by it's own relay...
  10. CDRIVE

    LED Signal Dummy load

    Yes Steve, that's what I was describing in post #32 in place of R2 in my schematic. Chris
  11. CDRIVE

    LED Signal Dummy load

    I was describing something like this. Just make believe the probes are Alligator Clips. :) BTW, I don't understand why you'd need 4 of these (for each signal control head) since your testing the current sensing relay not the LED strings. If I understood you correctly there's only 1 CSR for all...
  12. CDRIVE

    LED Signal Dummy load

    Hop, I was thinking a bit differently about the indicator LED that he wants. Wiring it as you describe will work but it doesn't garantee that the current relay is drawing his required 300mA min. It's unlikely but what I'm saying is if the dummy load resistor ever opened the LED would still...
  13. CDRIVE

    LED Signal Dummy load

    OK, you've lost me again. Your first schematic indicates 4 possible LED strings that may be switched on by what I think are relay contacts or SSR's [Rectangle] shown in each LED string. If you're using a dummy load to trip the ECR while any of those contacts are closed that LED string is still...
  14. CDRIVE

    LED Signal Dummy load

    I didn't want to chance that you'd miss this, so I didn't want to edit my last post. If you can post the specs of the ECR it would be a great help. If you can't find that then a manufacturer's Model/Part Number would probably suffice. Odds are there's an on-line datasheet available. Chris
  15. CDRIVE

    LED Signal Dummy load

    lxlramlxl, I suspect that your requirements are far simpler than we tend to (sometimes) make things. If all you're desirous of doing is activating a current controlled relay then all you need is a power resistor like this. This 400Ω resistor will pull 300mA @ 120V and is rated at 50Watts. Ebay...
  16. CDRIVE

    LED Signal Dummy load

    I should have caught this before making my last post but your description seems to indicate that you want to build a portable test instrument to take to the field with you. It also suggests that you don't want to be illuminating the traffic lights to make the test. Hence the need for the dummy...
  17. CDRIVE

    LED Signal Dummy load

    If I'm reading those relay specs correctly this relay coil will drop about 3.24VAC/50Hz @ 108mA. Chris
  18. CDRIVE

    LED Signal Dummy load

    lxlramlxl, welcome to Electronics Point. Many times a schematic like you posted answers a lot of questions. Often though, it doesn't. This may be one of those times. Your circuit appears to be powered directly from the AC Mains but I may be wrong. The best way to get accurate replies is to...
  19. CDRIVE

    Creating a variable wien bridge oscillator

    Yes, including this old girl (HP 200) that was extremely popular for many decades after its birth. It touted exceptionally low distortion over its frequency range. Chris
  20. CDRIVE

    Grounding and Circuit Noise

    Uh, Jeff Goldblum (Jurassic Park) said something like that! :D Chris
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