----- Original Message -----
From: "Dave King" <kingdws@SHAW.CA>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, February 13, 2002 2:04 PM
Subject: Re: [PIC]:interfacing power transitor


> >Select R's to ensure full saturation of both transistors
> >
> >You may also want a resistor between PNP base and +V to ensure it remains
in
> >cutoff when 2N2222 isn't driven.
> >
> >Bob Ammerman
> >RAm Systems
>
> Thanks Bob!
>
> This was close to what I had tried with a few differences. I used a ZTX851
> as one of the
> other fellows suggested as well as your suggestions and it worked (sort
of).
>
> It's now functional but I need to clean up the signal a bit more to make
it
> perfect.
> On the scope it would be best described as somewhat ugly and grungy. I've
also
> lost my clean square wave and have a saw tooth now.
>
> Cheers
>
> Dave

Sounds like one or more of the following:

The source impedence on your signal is a bit high.

You have some capacitance floating around that is slowing transitions.

Your R's are too high and you are not driving the transistors fully into
saturation.

Q: Refresh my memory:

1: source of signal

2: frequency of signal

3: duty cycle of signal


Bob Ammerman
RAm Systems

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