Since in potentiometer we control it by rotate its knob anticlock wise or clock wise...so in that place i want to control it by using MOSFET and Arduino means the working of the knob i want to control it automatically by giving signal from the Arduino after sensing...so is there any possibilities of doing this...in short I want to use Arduino MOSFET in place of potentiometer so rotating of knob is not required...
the R1 is the potentiometer i want to use this point automatically with the help of arduino
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3\$\begingroup\$ A MOSFET can operate as a voltage-controlled resistor (VCR) but it's quite hard since the ohmic region of a MOSFET is very narrow and thus hard to tune. \$\endgroup\$– Rohat KılıçCommented Oct 17, 2020 at 12:44
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1\$\begingroup\$ You need to show the circuit you are proposing to modify. You are suggesting using the MOSFET as a variable resistor. But a potentiometer is more than a variable resistor - it's a pair of variable resistors that add to a constant value. (As one goes up the other goes down.) Your schematic should show us the configuration and you should add notes to explain the maximum and minimum voltage (and whether it goes negative) in and what you are driving. Have you considered a digital potentiometer? Edit all the information into your question. \$\endgroup\$– TransistorCommented Oct 17, 2020 at 12:56
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\$\begingroup\$ I changed it take a look \$\endgroup\$– JacobCommented Oct 17, 2020 at 13:17
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1\$\begingroup\$ Right, that's different. Please edit to include a link to the datasheet you're using. You're using R1 as a variable resistor. You could probably use it as a potentiometer by eliminating R2 and R3, connect FLOAT to GND and the wiper to the regulator. The datasheet may give us a clue. \$\endgroup\$– TransistorCommented Oct 17, 2020 at 13:23
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4\$\begingroup\$ You'd be better off using a "digital potentiometer" controlled by the Arduino. \$\endgroup\$– user16324Commented Oct 17, 2020 at 13:26
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1 Answer
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My comment about using a MOSFET as a variable resistor was a general suggestion (before the presence of the schematic), now it became nearly meaningless after seeing the schematic.
It appears that your aim is to adjust the output voltage via the Arduino. Then you have these options:
- As the schematic is a Boost Converter, you can simply remove the IC, place the MOSFET in place of the IC and drive it with PWM coming from Arduino. You can use the analog inputs to measure the output and to modify the PWM duty-cycle and adjust the output voltage: Measure the output through the divider -> adjust the PWM duty-cycle -> measure the output again -> adjust the duty cycle again -> ...
simulate this circuit – Schematic created using CircuitLab
Fig: Principle schematic of an Arduino-controlled Boost Converter.
As already stated by others, you can use a digital potentiometer (make sure the voltage across the digi-pot does not exceed the abs max voltage).
You can use a DAC to directly adjust the output. Here is a tutorial of mine. Note that there's no need to use a DAC IC. Instead, you can build a crude DAC with PWM + RC Filter + Opamp Buffer.
answered Oct 17, 2020 at 14:04