Transistor Arrays

Discussion in 'General Electronics Chat' started by Blowerman, Jan 20, 2014.

  1. Blowerman

    Thread Starter New Member

    Jan 20, 2014
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    Can anyone help? I'm a complete electronics novice bar a few 555 related build projects. I want to see if a note switching system could be built using transistor arrays. This is a pipe organ application so each keyboard has a set of inputs and these then output to magnets. The reason for the trasistor based switching is to allow small current inputs to control the larger current magnets and also to allow the coupling of keyboards, where one keyboard can operate more than one department but only in one direction. Also to allow for an extended set of magnets to be connected to a keyboard from two different points effectively an octave say apart so that two stops at different pitches can be gained from one set of pipes. It's a very simple application but the basic transistor switching systems are quite builky and I wondered if this bulk could be reduced by using a transistor array type chip. All suggestions gratefully received.
     
  2. Brevor

    Active Member

    Apr 9, 2011
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    Sure a transistor array can be used to replace discrete transistors. You would need to determine how much current would need to be switched and select the transistor arrays accordingly. Years ago I worked at a company that made organs and electronic keyboards, We eventually went to a system that used serial data to replace most of the wiring from the keyboards to the keyers.
     
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  3. t06afre

    AAC Fanatic!

    May 11, 2009
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  4. Blowerman

    Thread Starter New Member

    Jan 20, 2014
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    Generally I use high resistance magnets about 140 Ohms but there may be need to fit switching to higher current magnets which are usually about 50 Ohms so the switching current can be in the range 107 -300mA. Thanks for the info on the chip certainly the more transistors on one chip the better. Presumably the outputs would need spark suppression to avoid any high voltage feedback from the magnets when switching off? Also with a chip such as this the input output is clear but not, to me admittedly, where the stop or coupler signal would go in to allow the switching to take place. Sorry not very technical speak as not very technical!
     
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