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From: firstname.lastname@example.org (Ken Smith)
Subject: Re: Problem
Date: Tue, 17 Dec 2002 22:23:27 +0000 (UTC)
Organization: a2i network
NNTP-Posting-Date: Tue, 17 Dec 2002 22:23:27 +0000 (UTC)
X-Newsreader: trn 4.0-test76 (Apr 2, 2001)
Originator: email@example.com (Ken Smith)
In article <firstname.lastname@example.org>,
Rudolf Maier wrote:
>square wave output, variable frequency control: 5-20KHz.
Is that 5Hz to 20KHz or 5KHz to 20KHz?
You can get the basic frequency with a CD4060 or 74HC4060 running off the
5V supply. Using a divide by 2 chip gives 50-50 duty cycle easily.
Look at the data sheet for the CD4060 and put a pot in for the resistor in
the RC oscillator.
>output amplitude: 1-10Vpp.
Pick a good quad op-amp.
Buffer the signal from the 4060 and run it into a 10 turn pot.
The wiper of the pot goes to a x2 gain non-inverting amplifier.
Put another pot between the +5 and ground. Buffer its wiper with another
section of the quad op-amp.
Don't ground the resistor used for the gain in (3) hook it to the output
of the op-amp in (4) instead.
Put a resistor between the output of the op-amp in (3) and your
circuits load. 100 Ohms should be enough.
Hook the left over op-amp as a voltage follower and use it to buffer the
op-amp in (3) and drive another 100 ohms going to the load.
Use the left over op-amp and a couple of transistors to make a power
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