i mean i used opamp for amplifying sine wave . can you give any advice other component instead of mine providing same functionView attachment 273945
The project basically provide gain any multiplier using op amp and mosfet part make the project adjustable gain using noninverting formula This is the project i have finished . Anyone else have an idea for design same specifiaction ?
What exactly is the specification? Voltage/current/frequency/price limits/ranges ?same specification ?
Hello there,View attachment 273945
The project basically provide gain any multiplier using op amp and mosfet part make the project adjustable gain using noninverting formula This is the project i have finished . Anyone else have an idea for design same specifiaction ?
It's an attempt to create an amplifier that has external variable gain control."... that meets the same function in this project?"
Well now, that is the whole point: What is the required function of this circuit? Novel circuit designs do not explain themselves; especially if the circuit has been designed poorly or wrongly. Does anyone here actually know just what this circuit is supposed to do?
That doesn’t matter provided that the voltage on the MOSFET doesn’t go lower than -0.5V (i.e. the body diode doesn’t start to conduct)Second, do the mosfets work with a negative voltage as well as a positive voltage? The input sine goes plus and minus doesnt it? That means the mosfets drains go plus and minus referenced to ground. Can you find a way to fix that?
Sir i'm explaining , if i 'm wrong ,i already give dc offset, drain part of mosfet is not exposed to negative alternance.For zener diodeHello there,
It looks like there could be some problems with this circuit.
First, what is the zener for and why is it on the output of an op amp?
Second, do the mosfets work with a negative voltage as well as a positive voltage? The input sine goes plus and minus doesnt it? That means the mosfets drains go plus and minus referenced to ground. Can you find a way to fix that?
right !It's an attempt to create an amplifier that has external variable gain control.
unfortunately i didn't find 3.3v zener i used 4.7v in simulationSir i'm explaining , if i 'm wrong ,i already give dc offset, drain part of mosfet is not exposed to negative alternance.For zener diode
Let's say I increased the input signal to 100 mv with100 mv dc offset ,will be taken at the last 20 times, 2 v came, then 3 times output 6 came 3.3v zener will keep it constant as 3.3 for the controller.
yeah i confirmed.The signal is 1 khz . Gain factor is given before the project my mentor said "i want to see the signal is amplified by 2 ,selectible,and 3 times. he said "do somehow you do"Please post your .asc sim file.
Can you confirm the aim of this project is to amplify a small amplitude AC input signal, using a controllable-gain amplifier, to provide a signal limited to 0V to +3,3V suitable for input to a microcontroller?
How much signal distortion (apart from a DC offset) can be tolerated?
Does the amplifier gain factor need to be known accurately?
Hi,That doesn’t matter provided that the voltage on the MOSFET doesn’t go lower than -0.5V (i.e. the body diode doesn’t start to conduct)
But I would suggest a digitally controlled potentiometer, of which there are hundreds available, with all sorts of different control systems, SPI, I2C, up/down buttons etc.
Hi,ANYONE ELSE have a suggestion?
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