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  1. Path: sparky!uunet!ogicse!news.u.washington.edu!raven.alaska.edu!news.acns.nwu.edu!uicvm.uic.edu!u40348
  2. From: U40348@uicvm.uic.edu (Jay Lorenzana)
  3. Newsgroups: sci.electronics
  4. Subject: JFET, HEXFET, SCR... Which one?
  5. Message-ID: <92309.224918U40348@uicvm.uic.edu>
  6. Date: 5 Nov 92 04:49:18 GMT
  7. Article-I.D.: uicvm.92309.224918U40348
  8. Organization: University of Illinois at Chicago
  9. Lines: 49
  10.  
  11.  
  12. Dear Net:
  13.  
  14. I am trying to decide on a switching device to control
  15. the power delivered to a line, and I need help.
  16.  
  17. The circuit is as follows:
  18.  
  19. -------
  20.       |        -----------------------------
  21.  HCMOS|        |    |                      |
  22.       |    |-------S2                      |
  23.       |    |   |    |                      |
  24.      A|--------S1   |                      |
  25.       |        |    |                    R Load
  26.       |        |    |                      |
  27. -------       +15  -15                     |
  28.                |    |                      |
  29.                -----------------------------
  30.                |
  31.                 grnd
  32. Given:
  33. Line A controls Switch 1 and Switch 2, S1 and S2 respectively.
  34. When S1 is open S2 must be closed and vice versa.
  35. Switching speed = 9600 baud =~ 10khz.
  36. Current thru Load = +-5Amps, +-20A spike.
  37. Circuit is isolated from chip via opto-isolator.
  38.  
  39.  
  40. Question:
  41. What solid state device would work best and cost least
  42. for S1 and S2?
  43.  
  44. I have thought about using NPN/PNP, JFETS, P/N-CHANNEL HEXFET,
  45. and SRC's, type setups.  But what's the BIG difference?  I prefer
  46. using the SRC's because they are least expensive, but I have
  47. read that SRC stay on even when the gate is relieved if
  48. there is large currents...... Please help.
  49.  
  50. Thanks in advance,
  51.                   Jay
  52.  
  53.  
  54.  
  55.          Univeristy of Illinois
  56.                at Chicago
  57.  
  58.                                    Internet: U40348@uicvm.uic.edu
  59.                                    Bitnet  : U40348@uicvm.bitnet
  60.