I have one question though. Why the choice of potentiometes in the circuit, why not fixed resistor?
any idea of the purpose of the potentiometers in this circuit?
I have one question though. Why the choice of potentiometes in the circuit, why not fixed resistor?
any idea of the purpose of the potentiometers in this circuit?
Both potentiometers set the output frequency. They should be the same value if the 1nF capacitors are the same value.
Of course the potentiometers can be fixed resistors but then the frequency will be fixed.
Yes but nobody makes a 5k fixed resistor.
If the resistors are both 5.1k ohms and the capacitors are both exactly 1nF then the frequency will be about 31.3kHz.
Don't you want 40khz? If the resistors are 3.9k ohms then the frequency will be about 41kHz.
If the resistors are both 5.1k ohms and the capacitors are both exactly 1nF then the frequency will be about 31.3kHz.
Don't you want 40khz? If the resistors are 3.9k ohms then the frequency will be about 41kHz.
Understood. By the way, theres this thing I have been meaning to ask, how do you calculate the frequency (meaning the exact formula for this circuit, and i take it it uses R4, R5, C5 and C6)?
The amplifier is a non-inverting type with its gain (Rf/R3) + 1 but Rf is R1 plus R2. R1 is paralleled by 2 diodes to set the output level.
The gain for a Wien Bridge oscillator needs to be a little more than 3. The gain without the diodes is (1k + 3.9K)/2.2k + 1= 3.23 and the diodes reduce the gain a little if the output tries to become too high.
Hi Eric...I actually decided to download LTSPICE and work with it. It is really more interesting than PSPICE from my point of view.
The potentiometer and the opamp, I was able to add from help of one of your other thread. But I have a question concerning the opamp value, it is given by R value and wiper value. what is the wiper value for? and how do we choose it? why should we have the wiper value? how did you choose the wiper value for the schematic you provided?
Hope it is not too much question, but I just want to understand the wiper thing.
oh thanks. Can you share GP5V0.sub and asy if you can please. And for the first schematic you shared, is it 10k pot or 5k pot? coz all i see is two 5k pots with different wiper values. sorry for asking too many questions, im just not too familiar with pots.
oh thanks. Can you share GP5V0.sub and asy if you can please. And for the first schematic you shared, is it 10k pot or 5k pot? coz all i see is two 5k pots with different wiper values. sorry for asking too many questions, im just not too familiar with pots.