transistor help

Guest · Posted: Thu Nov 15, 2007 5:14 pm Post subject: transistor help

I am looking for a transistor that when its base or gate is not powered, it completes the circuit and when its base or gate is powered it breaks the circuit. Is posible to get this kind of transistor? Thanks

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

A single JFET(w/bleeder) can be utilized as opposed to a BJT . Here's an example

http://www.allaboutcircuits.com/vol_3/chpt_5/2.html

hotwaterwizard · Joined: 26 Nov 2004 Posts: 72

A Logic Not Circuit or Inverter would do the trick.
It has the opposite output than what is at the input.
It can be made out of one Transistor.

http://www.flatspike.com/projects/electronics/single-transistor-logic-inverter/

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John DeRosa
(Hotwaterwizard)
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Guest · Posted: Mon Dec 03, 2007 5:34 pm Post subject:

i don't know powered what it means a pnp neg will conduct pos will not. you ask an inpossible questionthat makes no sense to me but you have recieved one replay on how to do it .