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A piece of lab equipment (an image intensifier) is controlled by voltage in the range of 0..5V (current is expected to be in the range of 10 mA; desired resolution is around 12 bits; no frequency requirements since we won't be changing the voltage much). The internal voltage of the intensifier is set to 500V + (850V - 500V) / 5V * Vc. I would like to make it a part of a larger apparatus, all controlled by a PC. Therefore, I need the PC to control a DAC.

What would be a simple way to do that? Should I look for a microcontroller with a real DAC (not PWM) in 5V range? (Those I found seem to be limited to 3.3V - perhaps I didn't look in the right places?) Should I buy a simpler microcontroller and a separate DAC controlled by I2C? Use a 3.3V DAC with an operational amplifier?

It is not a problem for me to write a PC or uC program, but I don't have any successful circuit building experience, so I would like to optimize for less building complexity.

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. Any conclusions reached should be edited back into the question and/or any answer(s). \$\endgroup\$ – Dave Tweed Sep 24 at 16:53
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Here is one example of a USB to 12 bit DAC for around $80.

Typical applications include variable air damper control, blower and motor speed control, light level control, audio sound level control, motion control, water/fluid/air valve position control, variable-frequency drive (VFD) motor control, 4-20ma loop control, solenoid position control and hundreds of other applications. Connects to USB - Powered from USB port 4 channels of 10 bit Digital to Analog (1,024 increments in output level) with DAC-4U10 4 channels of 12 bit Digital to Analog (4,096 increments in output level) with DAC-4U12 Selectable reference voltage - allows for 0 to 3.3v, 0 to 5v or user supplied voltage output ranges Available with high precision voltage reference pre-installed. Allows for (0 to 1.2v), (0 to 2.048v - .5mV per increment), (0 to 2.5v), (0 to 3v) or (0 to 4.096v - 1mV per increment) output ranges

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    \$\begingroup\$ We ended up buying the USB DAC. I also ordered an ATtiny85 clone pre-flashed with a USB bootloader and an I2C display to gain some experience in communicating between USB and I2C peripherals in my spare time. \$\endgroup\$ – aitap Oct 15 at 15:26
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Not having much successful circuit building experience doesn't sound hugely promising but here goes for a potential solution to your problem.

If you have a microcontroller lying around already then an R2R ladder DAC with a unity gain voltage buffer at it's output would do the job for not needing to change often/quickly, being cheap and being controllable form a PC. You could just about do this with an Arduino UNO and Arduino IDE as you don't have to worry too much about how slow the digitalWrite() method is.

schematic

simulate this circuit – Schematic created using CircuitLab

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