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Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
Subject: Re: Transistor Switching
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
X-Inktomi-Trace: public1-pete2-5-cust19.pete.broadband.ntl.com 1031724842 6325 184.108.40.206 (11 Sep 2002 06:14:02 GMT)
Date: Wed, 11 Sep 2002 07:14:01 +0100
NNTP-Posting-Date: Wed, 11 Sep 2002 07:14:02 BST
"Chuck Simmons" wrote in message
> Tim wrote:
> > My electronics instructor demonstrated a transistor amplifier
> > that had a small gain. He used a signal generator to apply
> > a ac signal to the base. Later he mentioned something about
> > a transistor oscillator than had a frequency of 20 KHz. He totally
> > lost me. How can a bipolar transistor be configured to self
> > oscillate at 20 KHz.
> You only really need a gain of one or slightly more to make an
> oscillator. Then the output is connected to the input with a circuit
> that selects the desired frquency. You would be surprised at how often
> this happens by accident. I don't know how much you know about AC
> circuits so I can't detail an example. Except for a very unusual case,
> single transistor oscillator will require at least an inductor and a
> capacitor in addition to bias resistors. (Unless someone knows about
> another exception not involving mechanical resonators.)
Er... You can use a 3 stage RC from collector to base to make a single
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