Re: Driving tri-state LED matrix

On May 30, 3:53 pm, "MK" <nos...@xxxxxxxxxx> wrote:

In your circuit a big current will flow from VCC
through the emitter and out of the base of the first (leftmost) PNP
transistor, into the base and out of the emitter of the NPN transistor. The
second PNP transistor will turn on, the first two transistors will be
destroyed.


See this is exactly what I was thinking... but miraculously this
worked perfectly in my college project. Even if my board mixed up the
collector with the emitter for one of the transistors, it still
doesn't explain why both transistors weren't always turned on... ?!
.

Relevant Pages

  • Re: Newbie transistor question
    ... I'm having trouble getting a transistor to work the way I thought it ... the collector is tied to +5 and the emitter to ... The emitter shows +4V (5 ... you expect operation with both collector and base voltage at 5 volts (no extra positive collector voltage to keep the gain up). ...
    (sci.electronics.design)
  • Re: Amplify 1.5v DC to 5v DC?
    ... with the transistor being a 2N3904. ... in that example the emitter resistor is required because the input ... >one NPN feeding in to the base of another NPN? ...
    (sci.electronics.basics)
  • Re: quick emitter follower question
    ... I'm thinking about using a simple 1 transistor emitter follower ... will there be no noise added since there is no amplification ... The smaller the load, the more the ...
    (sci.electronics.basics)
  • Re: Transistors
    ... What should I consider to do regarding DC biasing of the transistor ... Collector to V+ through a 1K resistor. ... The key voltage is between the base and emitter. ...
    (sci.electronics.design)
  • Re: Driving tri-state LED matrix
    ... Are you talking about the way the emitter on the PNP is the bottom pin ... There is a reason for transistor symbols looking a bit like a diode between ... In your circuit a big current will flow from VCC ...
    (comp.arch.embedded)