In today’s tech-driven world, wearable sensors are becoming increasingly popular. Whether it’s for fitness tracking or health monitoring, these sensors require low voltage to ensure energy efficiency and longer battery life. However, a common issue that engineers and hobbyists face when designing low-voltage sensors is ensuring that the system operates reliably without draining the battery too quickly or generating excess heat. The solution lies in selecting the right components and optimizing the circuit for low power consumption.

The Problem :

Low-voltage circuits often suffer from power loss or insufficient performance due to improper selection of components. For example, if the resistor values aren’t chosen correctly, the sensor may draw more current than necessary, leading to rapid battery drain. This can be fixed by calculating the correct resistor values to limit the current.

Practical Example :

Imagine you’re building a simple wearable health monitor, powered by a 3.7V Li-ion battery.

If you use an incorrect resistor in the sensor’s current-limiting circuit, it could drain the battery too fast, shortening the device’s lifespan.

To fix this, you’d need to calculate the correct resistor value using Ohm’s Law:

V = IR.

For a current of 20mA, with a 3.7V battery, the resistor needed would be:

R = V / I = 3.7V / 0.02A = 185 ohms.

Sample Calculation :

For a sensor using a 3.7V battery and drawing 20mA of current, the resistor required for proper current limiting is 185 ohms, as calculated above.

Suggested Products :

For building your own wearable sensor project, consider using MOSFETs and flux for efficient power control and soldering. Check out Made in India MOSFETs and Made in India flux at SmartXProKits.in.
Shop now at SmartXProKits.in to get quality components for your next project. Support our work and India’s innovation—buy from our Make in India site!