Ohm's Law: V = I × R
- V = Voltage (volts)
- I = Current (amperes)
- R = Resistance (ohms)
🔋 DC Electricity & Water Analogy
VΩ
Current: A
DC
Volt
Ohm
🔍 DC View
- Voltage pushes current in one direction.
- Resistance restricts the flow like a narrow pipe.
- Current flows steady in one direction:
I = V / R
🔄 AC Electricity & Water Analogy
VΩ
Current: A
AC Source
Load
🔍 AC View
- Alternating Current (AC) changes direction continuously (like back-and-forth water).
- Resistance restricts how much current can move.
- Current calculated using RMS:
I = V / R
Basic Electricity Course
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Ohm's Law
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Wire Gauges and Ampacity
| Wire Gauge (AWG) | Diameter (mm) | Max Ampacity (A) | Applications |
|---|---|---|---|
| 14 | 1.63 | 15 | Lighting, small appliances |
| 12 | 2.05 | 20 | General household circuits |
| 10 | 2.59 | 30 | Kitchen appliances, water heaters |
| 8 | 3.26 | 40 | Electric ranges, dryers |
| 6 | 4.11 | 55 | Electric heaters, large appliances |
Circuit Loads and Power
Power = Voltage × Current (P = V × I)
- P = Power (watts)
- V = Voltage (volts)
- I = Current (amperes)
Circuit Load Calculator
Total Power: 0 W
Total Current: 0 A
Circuit Status: OK
Voltage Classifications
Low Voltage: Up to 600V
High Voltage: Above 600V
Knowing these classifications helps engineers identify potential hazards and ensure compliance with electrical codes.
Electrical Safety Tips for Fire Prevention
- Don’t overload circuits — know the amperage limits.
- Use the correct wire gauge for each application.
- Install GFCIs in bathrooms, kitchens, and outdoor locations.
- Inspect cords and outlets for damage or wear.
- Keep flammables away from electrical equipment.
AC vs DC Power
DC (Direct Current) flows in one direction and is commonly used in batteries and electronics.
AC (Alternating Current) switches direction and is used for household and commercial power because it's more efficient for long-distance transmission.
Grounding and Safety
Grounding ensures that stray electrical current is safely directed into the earth, reducing the risk of electrical shock and fire.
Neutral wires help return current to the power source. In moisture-prone areas, GFCIs are required to add an extra layer of protection.
GFCI Operation Simulation
Imagine a device plugged into a GFCI outlet. If the current leaving the hot wire is not equal to the current returning via the neutral wire, the GFCI detects the imbalance and cuts power.
System Normal