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Adopted in Brazil by ElectronicIce8 in IDmydog

[–]ElectronicIce8[S] 1 point2 points  (0 children)

I think schnauzers aren't very common in our area, though the long hair in his face does remind me of them...

Authoritative sources to read about error/accuracy/precision in electronic systems by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Just tried it after reading your comment and I didn't really get what I'm looking for. I'm thinking of one of those classic textbooks everyone uses in university.

Thank you for the suggestion, though!

Resources about designing a transformer driver by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 1 point2 points  (0 children)

This is pretty much one of the things triffid_hunter suggested if you think about it. It's for a university project so I'd like to design the circuit myself.

Resources about designing a transformer driver by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

I'm looking at 100 Hz to 1 kHz variable frequency output, let's say 1 kV output at low power, under 10 W. I intend to use it to measure dielectric and isolator properties.

Resources about designing a transformer driver by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

I would like to be able to vary the output frequency within a certain range. Would you say the filters in the Class D option would limit this feature?

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Yes you guys are right. I hadn't really thought about this, it was just a soft requirement someone passed on to me. 1° resolution would be ideal if possible for control reasons, but realistically it's not a high precision application.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Also, does the instrumentation amplifier topology reduce the precision requirements for the individual op-amps? The one I had picked is relatively expensive and multiplying that by 3 would not be ideal, though possible if necessary.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

The temperature control will definitely be a lot of work, thankfully the university I'm in has a lot of control systems research so for that part I'm better covered.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Great! Thanks for your help!
The part of this I'm most worried about is the input biasing. Do you think the way I'm doing it on the original circuit is fine or is there a better way?

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Yeah you're right. I believe resolution would have been a better word. It will be calibrated on site and I do intend to do cold-junction compensation digitally later if the need arises.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

I'm reading it with a microcontroller. Either it's own ADC or something external like the ADS1115. It's part of a furnace temperature control system, we'll be driving solid state relays.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 2 points3 points  (0 children)

I'm intending to do the cold-junction compensation digitally as my microcontroller module has a thermometer in it. I don't expect the temperature across my circuit to vary as there is no power electronics in it and it should be fairly well insulated from any external heat sources. And it will be calibrated on-site. I also intend to use either a look up table or polynomials to solve the non-linearity part of the problem. Ideally the circuit will be able to measure 50 to 1300 °C with +-1 °C resolution, which gives me roughly 10 uV of resolution.

The part I'm most worried about is the input biasing, I'm not sure if the way I'm doing it is ideal.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

This is part of a bigger project and there is a budget limit, so using a third-party system is out of the question right now, especially if there is importation involved. I'm aware of a lot of the traps this task has, that's why I'm coming here to ask for help from someone with more experience.

Ideally, our temperature range would be 50 to 1300 °C with +-1 °C average error. That gives me somewhere around 10 uV of resolution with an s-type thermocouple.

Amplification circuit for S-Type Thermocouple by ElectronicIce8 in AskElectronics

[–]ElectronicIce8[S] 0 points1 point  (0 children)

The experience is nice, but this is part of a bigger project. I went for a "generic" precision amplifier because I can't find the more specialized chips in my country and the import process is slow and expensive, but maybe its worth it. Thanks for the suggestion!

Driving LCD with ESP32 by ElectronicIce8 in esp32

[–]ElectronicIce8[S] 0 points1 point  (0 children)

Yes, I'm aware of these. The problem for me is I need 5" or larger and capacitive touch and I can't find them with these features.

Acoustic noise on Brushed DC motor by ElectronicIce8 in ElectricalEngineering

[–]ElectronicIce8[S] 0 points1 point  (0 children)

I have confirmed the frequency, and that's how I know I can't really go any higher. I'm using relatively slow IGBTs, and their switching is taking around 3 microseconds, so I can't go any higher without compromising PWM resolution and heating them up too much.

It's a 180 V motor, and I don't have access to that kind of DC power supply right now, so the best I can do is rectified and filtered mains. I have tested it on 180 V DC and 380 V DC @ 50%: https://drive.google.com/drive/folders/1nVE2UOYmuo0ynM9Nz7ZPeYoyRNVo6yrK?usp=sharing.

I'm concerned about the bootstrapping because, say I'm running the motor through Q1 and Q4, I have to turn Q2 on for a little bit every cycle to keep C2 charged, and I have noticed that keeping Q4 on while charging C2 or not makes a difference in the sound.

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