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St. John Tech Club -- Robotics --. May 2012. What is Ohms Law?. A relationship between Voltage, Current and Resistance in any DC electrical circuit. Discovered by the German physicist Georg Ohm , (1787 - 1854). By knowing two of the values, you can calculate the third.
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St. John Tech Club -- Robotics -- May 2012
What is Ohms Law? • A relationship between Voltage, Current and Resistance in any DC electrical circuit. • Discovered by the German physicist Georg Ohm, (1787 - 1854). • By knowing two of the values, you can calculate the third.
Review of voltage & current • Circuit is a path that electricity (free electrons) takes • Voltage is the “force” that causes electric charge to move • Electric current is the FLOW of electric charges (electrons)
What is resistance? • Resistance is a measure of how much an object opposes the passage of electrons. • Unit is the “ohm”, Ω. • The internal resistance of the human body has a range from 300 to 1000 ohms, depending on path electricity takes through the body, skin
Ohms Law Triangle V = Voltage I = Current R = Resistance One volt will push one amp through one ohm of resistance. Greater Resistance => less Current for a constant Voltage
How to apply Ohm’s Law • LED Circuit • An LED circuit needs a current-limiting resistor in the circuit to protect the LED R = resistance Current = I V=Voltage
Why is Ohms Law important? • It explains how the most important concepts of electricity relate to each other. • Anyone working with electricity uses it. • It is the “Newton’s Law of Motion” for electricity. • It allows us to enjoy anything electrical such as appliances – TVs, refrigerators and stereos.