Dc Electricity Flashcards
What is voltage and its unit?
Voltage gives electrons the energy to move around a circuit and comes from a power supply. It is measured in V, volts.
What is Current and its unit?
Current is the flow of charge around a circuit or through a component. It has symbol I and is measured in A, Amps.
What is resistance and it’s unit?
Resistance is the opposition of current, symbol R measured in ohms.
What happens to current and voltage in a series circuit?
In a series circuit, the current that flows through each of the components is the same, and the voltage across the circuit is the sum of the individual voltage drops across each component.
What happens to resistance in parallel circuits?
If two resistors are in parallel, the resistance of those resistors is equal to 1/R = 1/R1 +1/R2 using cross multiplication to find R.
What happens to current in parallel circuit?
Current splits into each branch based on its resistance. if there is 1 ohm of R in branch 1 and 1 ohm of resistance in branch 2, the current split equally. However, if there is no resistance in one branch (e.g an ammeter in parallel), all of the current will go through the branch with no resistance, giving the other branch no current.
What happens to voltage in a parallel circuit?
Voltage splits equally between branches and the voltage drop across each component equals the voltage of the power source.
What is ohm’s law?
V = IR
What is the difference between V = IR in the whole circuit and in single components?
In a full circuit, V is the voltage of the power source, I is the total current and R is the total resistance. In a single component, V is the voltage loss across that component, I is the current passing through the component and R is the resistance of the component.
Why is voltage “across?”
Because we are describing the voltage loss “across” a component.
Why is current “through”?
Because current travels in one direction through components from the positive terminal to the negative terminal.
Current is the measure of charge over time, what is the formula?
I = q/t
