Measuring Resistor Resistance with Microcontroller
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Below is a list of recommended components along with links that you can add to your Flux project for a low-value resistor measurement circuit using a 3.3V microcontroller:
Table
| Component Type | Part & Link | Details |
|---|---|---|
| Instrumentation Amplifier | INA333 | Precision, low-offset amplifier for accurately sensing the small voltage drop across the resistor. |
| Precision Op-Amp (for current source feedback, if needed) | OPA333 | Rail-to-rail, ultra-low offset op amp for implementing a stable constant current source with low-voltage operation. |
| N-Channel MOSFET (optional, for current control) | AO3400A | Low R_DS(on) MOSFET suitable for precision current driving circuits using a feedback loop. |
| Precision Sense Resistor | R1 | A low-value resistor (e.g., 1Ω–10Ω, 1% tolerance) to set the constant current and act as the measurement element. |
| Decoupling Capacitor | C1 | A 0.1µF capacitor for the op amp’s supply decoupling to ensure stable operation. |
These components let you generate a known constant current through the resistor and then amplify the low differential voltage (using the instrumentation amplifier) so your microcontroller’s ADC can measure it accurately.
Would you like more detailed guidance on incorporating these components into your schematic within Flux?
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