DC circuits Flashcards
What is the relationship between current and voltage in a material that obeys Ohm’s Law?
The current through a material at a constant temperature is directly proportional to the voltage across it. This means that if you triple the voltage, the current will also triple.
What is necessary for the resistance of materials obeying Ohm’s Law to remain constant?
The temperature must remain constant for the resistance of materials obeying Ohm’s Law to remain constant.What does Kirchhoff’s Current Law state?
What remains constant for a given piece of material when it follows Ohm’s Law?
The quotient of voltage to current, which is called resistance, remains constant for a given piece of material when it follows Ohm’s Law.
What is the formula representing Ohm’s Law?
The formula representing Ohm’s Law is V=IR, where
V is the voltage in volts (V), I is the current in amperes (A), and R is the resistance in ohms (Ω).
What does Kirchhoff’s Current Law state?
Kirchhoff’s Current Law states that at any junction in an electrical circuit, the sum of currents flowing towards that point is equal to the sum of currents flowing away from it.
In what units is resistance measured?
Resistance is measured in ohms (Ω).
What does Kirchhoff’s Voltage Law state?
Kirchhoff’s Voltage Law states that the algebraic sum of all voltages around any closed loop in a circuit is zero.
How can Kirchhoff’s Current Law be used in a circuit?
Kirchhoff’s Current Law can be used to calculate unknown currents at a branching point in an electrical circuit.
What is the significance of Kirchhoff’s Voltage Law in a circuit?
Kirchhoff’s Voltage Law ensures that the total voltage around any closed loop in a circuit is zero, meaning that the voltage supplied is completely dropped across the components within the loop.
What is important to remember about voltage in Kirchhoff’s Voltage Law?
It is important to remember that voltage doesn’t exist at any single point but is a difference in potential between two points.
What is EMF in the context of a power source?
EMF (Electromotive Force) is the voltage provided by a power source such as a battery.
What happens to the terminal voltage when the switch is open?
When the switch is open, the terminal voltage is equal to the EMF because no current flows through the internal resistance (IR).
What happens to the terminal voltage when the switch is closed?
When the switch is closed, the terminal voltage is lower than the EMF because a current flows through the internal resistance (IR), creating a voltage drop across it.
What is the formula for terminal voltage when the supply is on-load?
The formula for terminal voltage when the supply is on-load is V=EMF−I x r where
V is the terminal voltage, I is the current, and r is the internal resistance.
What is short-circuit current?
Short-circuit current is the high current that flows when the terminals of the supply are directly connected, limited only by the internal resistance of the power source.
