Voltage, Current, and Resistance
Understand the fundamental concepts of electronics.
Understanding Electronics Fundamentals
To work effectively with Arduino and electronics, you need to understand three fundamental concepts: voltage, current, and resistance. Let's explore these through simple analogies.
Learning Through Analogy:
Think of an electronic circuit like a water system - it makes these concepts much easier to understand!
Get Your Arduino Kit
To follow along with our tutorials and experiment with these concepts:
Voltage (V)
What is Voltage?
Voltage is the electrical pressure or force that pushes electric charges through a circuit.
- Water Analogy - Like water pressure in a hose
- Measurement - Measured in Volts (V)
- Power Source - Provided by batteries or power supplies
- Arduino - Most Arduino boards use 5V or 3.3V
Just as higher water pressure pushes water more forcefully, higher voltage pushes electric charges with more force.
Current (I)
What is Current?
Current is the flow of electric charges through a circuit, similar to water flowing through a pipe.
- Water Analogy - Like the rate of water flow
- Measurement - Measured in Amperes (A) or milliamps (mA)
- Flow Direction - Moves from higher to lower voltage
- Arduino - Most Arduino pins can handle up to 20mA
Safety Note:
Too much current can damage components or create safety hazards. Always use appropriate resistors!
Resistance (R)
What is Resistance?
Resistance is the opposition to current flow in a circuit, like a narrow section in a water pipe.
- Water Analogy - Like a bottleneck in the pipe
- Measurement - Measured in Ohms (Ω)
- Purpose - Controls current flow and protects components
- Components - Resistors are the most common way to add resistance
Common resistor values in Arduino projects range from 220Ω to 10kΩ.
Ohm's Law
The relationship between voltage, current, and resistance is defined by Ohm's Law:
V = I × R
- V - Voltage in Volts (V)
- I - Current in Amperes (A)
- R - Resistance in Ohms (Ω)
Quick Calculations:
- Find Voltage: V = I × R
- Find Current: I = V ÷ R
- Find Resistance: R = V ÷ I
Practical Example
Let's calculate the current through an LED circuit:
Given Values
- Arduino Voltage - 5V from the board
- LED Resistor - 220Ω protection resistor
Calculate Current
I = V ÷ R = 5V ÷ 220Ω ≈ 0.023A or 23mA
Check Safety
23mA is slightly above the recommended 20mA, so we might want to use a 330Ω resistor instead
Component Protection:
Always include appropriate resistors to protect LEDs and other components from excessive current.
Common Applications
Understanding these concepts helps you:
- LED Projects - Calculate correct resistor values
- Sensor Reading - Understand voltage dividers
- Circuit Design - Create safe and efficient circuits
- Troubleshooting - Identify and fix circuit problems
Coming Up Next:
In our next episode, we'll apply these concepts to build more complex Arduino projects!
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