From: Fred Bloggs
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Subject: Re: Amplifying stage with negative Vgain??
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Date: Fri, 06 Dec 2002 15:28:50 GMT
NNTP-Posting-Date: Fri, 06 Dec 2002 07:28:50 PST
Organization: EarthLink Inc. -- http://www.EarthLink.net
Paul Burridge wrote:
> On Thu, 05 Dec 2002 16:10:35 GMT, Fred Bloggs
> opined thusly:
>>If the BC337 pinout is such that you have connected E to the input
>>junction of the 3k's, B to 12V, and C to the 1080 output resistor, then
>>you end up with a configuration that gets 2Vp-p across that 1080 for
>>8Vp-p at the input. You have almost certainly done something like this.
>>You can figure this out if you measure the quiescent DC voltages at the
>> three nodes- what are they?
> My data book states that this device *does* come in varying pin-outs,
> so it was one of the first things I checked out. However, the specific
> device concerned is a BC337-16 which (when looked at from above with
> the flat side to the left) has (from top to bottom) C, B & E
> respectively. The DC voltage readings are (WRT GND) 12.5, 6.1 & 5.5v
> respectively. And these are pretty much the voltages anyone would
> expect, IMV
Try flipping the transistor, exchanging C-E, anyway, see if the DC
measurements are nearly the same, and then try making the ac-measurement.