# Analog Temperature Sensing Prototype

Project Overview

This project is an Analog Temperature Sensing Board designed for Battery Management Systems (BMS). It utilizes an NTC Thermistor in a voltage divider topology to convert thermal changes into measurable analog voltage signals.

Technical Specifications

- Input Voltage (VCC): 5V DC (typical)

- Top Resistor (R1): 10kΩ Fixed (0805 SMD)

- Bottom Resistor (TH1): 10kΩ NTC Thermistor (0805 SMD)

- Output: Analog Voltage (Vout) via 2.54mm Header

Design & Layout

The PCB was designed using LibrePCB. The layout is optimized for a small form factor while maintaining clear signal paths between the power source and the microcontroller interface.

Simulation & Verification

To verify the circuit's accuracy, I performed an Operating Point (.op) analysis using Ngspice. This step ensures the hardware logic matches the mathematical model before manufacturing.

Mathematical Model

The output voltage is calculated using the Voltage Divider formula:

$$V_{out} = V_{in} \times \frac{R_{NTC}}{R_1 + R_{NTC}}$$

Simulation Results (Ngspice)

- Scenario 1 (Room Temp @ 25°C): $R_{NTC} = 10k\Omega \rightarrow V_{out} = 2.5V$

- Scenario 2 (High Temp): $R_{NTC} = 5k\Omega \rightarrow V_{out} = 1.66V$

Tools Used

- LibrePCB: Schematic Capture & PCB Layout

- Ngspice: Circuit Simulation & Verification

- GitHub: Documentation and Version Control