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  1. colum

    Op Amp 741

    Thanks for your swift reply Alec_t, what I want to do is generate 400 Hertz at 115 v to drive an old Analog frequency meter at about 7 Watts and then the circuit may be used for parts ...Thanks again for your Similar threads..colum
  2. colum

    Op Amp 741

    I am trying to find the wiring for a 741 Op Amp as a simple Buffer of a Sine Wave with a 15 + Volt and a 15 - Volt Regulated supply.. I hope my diagram shows up and if it doesn't I would appreciate advice on the pin numbering...Thanks...colum
  3. colum

    Power supply + and -

    Thanks Colin for that information 10 Volt is alot. I hope the capacitors will smooth things over but luckily this is not going to power any ICs just an old Synchronous motor and antique tuned reed meter...colum (jeff)
  4. colum

    Power supply + and -

    All my books show the pins as #1 #3 #2 which is incorrect your diagram is correct and thanks for your efforts Be well....colum...and thanks
  5. colum

    Power supply + and -

    Thanks again davenn, just one last thing is your ICs Pin layout 1-3-2 facing the front and i do appreciate all of the trouble you are going through ....colum (jeff)
  6. colum

    Power supply + and -

    Hi Dave, I checked the diagram again and it seems they mislabled Capacitors 4 and 5 instead of 3 and 4 so I wonder if you know anyone that actually built this circuit...I have found a circuit and built it and it was photocopied but the pin numbers were reversed and this was a well known...
  7. colum

    Power supply + and -

    Thanks Dave for that excellent diagram...Live long and prosper" -Spock Jeff
  8. colum

    Power supply + and -

    I want to make a Power supply using A 7812 + Volt and a 7912 - Volt for a dual supply but several of my books show different wiring for the 7912 -V so if someone would just tell me the simple wiring for the Transformer Center Tap (ground) and the -V in and the -V out , there are 3 legs left to...
  9. colum

    M.U.N.T.E.R. (Z80-based computer)

    I have quite a few chips that were rescued from an old Apple so if you could use any old chips let me know...colum
  10. colum

    Electric interference

    Thanks tehtehteh and Bluejets, I'm beginning to feel confident...Jeff
  11. colum

    Electric interference

    Hi shrtrnd. Thank you for the advice If I want to run a shielded cable I would have to drill a hole somewhere into the passenger compartment, I don't think there are any existing holes, that is the problem .
  12. colum

    Wanted: Free

    I have quite a few OLD Crystal timing generators that anyone can have if you tell me the Hertrz And also older ICs some are new some were pulled from early Apples etc I also have old electric gauges of different types that are quite heavy and you would pay postage only. If you were making an...
  13. colum

    Electric interference

    Hi Bluejets .I think I messed up this post, I'm new at this Thank you for your advice, I will try it with a small screen and seperate battery power if neccessary...Jeff
  14. colum

    Electric interference

    I bought a new car and want to install a wireless camera in the front licence plate so the signal would need to cross the engine so my question is---Would the auto Electric interfere with the wireless signal or would this need to be hard wired. I wonder if the generating of DC causes electric...
  15. colum

    For Sale: Antique gauges

    I have a collection of 2 kinds of Tuned Reed Vibration gauges one type measures frequency of AC supplied and ranges from 20 hz to 400hz and Lo volt to !25. All reeds vibrate but I cannot test the 400 hz The other Tuned Reed types are non electric and sense the RPM by making contact with the...
  16. colum

    IR Leds or Visible ?

    Thanks Adam for your reply, that clears that up, Be well....colum
  17. colum

    IR Leds or Visible ?

    i was under the impression that an Led light brightness could not be adjusted, if it called for a 300 ohm resistor at 12v that's what it needed Thanks for your advice...colum
  18. colum

    IR Leds or Visible ?

    Thanks Gryd3 for that very very good safety advice and advice on use of a digital camera
  19. colum

    IR Leds or Visible ?

    thanks Adam that explains it...colum
  20. colum

    IR Leds or Visible ?

    I want to run about 75 ft of Fiber Optic cable as an ON Off type of switch.. All of the LEDs that I have are IR, so my question is...Is IR better for long transmission and receiving or is visual Leds better since the activating light can be adjusted in intensity. Would it be better to use an...
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