Electrical Circuits Flashcards
What is Kirchoffs 2nd Law
Total Emf is equal to Total potential difference around a closed circuit.
Characteristics of a series circuit
The current has one path, and same at every point in the circuit. Emf is dispersed to components depending on their resistance, e.g, two components in a circuit with an emf of 10 volts, the component with 6 ohms resistance takes 6 volts while the components with 4 ohms resistance takes 4 volts. With Emf sources with opposing polarity, you minus the emfs instead of adding.
Characteristics of a parallel circuit
The current is split into the branches. The branches with the lower resistance gains the greater current. E.g, One branch has a resistance of 10 ohms, and the other has 20 ohms. A 3 amp current will be split into 2, with 2 amps in the 10 ohm branch and 1 amp in the 20 ohm branch. This is kirchoffs first law.
The emf in each branch will be the same as the total emf of the circuit. The components in the branch get distributed potential difference same as a series circuit. This is Kirchoffs 2nd law.
Adding resistance in circuits
In series, Add all resistances together to find the total resistance. In parallel, if multiple resistance on one branch, put them in the form 1/r and add them, then flip back to r.
What is internal resistance
When current flows through a power source, some energy gained by the charge carriers is transferred into heat, causing the terminal pd to be less than the emf of the power source. Called lost volts.
What is a potential divider
The arrangement of a circuit that purposefully divides the p.d supplied by a power source. Loading a component or circuit to a potential divided voltage in parallel causes the Voltage to decrease, as adding a component decreases the total resistance of the parallel branches.
