1. You need a power source
2. You need a load. Anything from a single resistor to a whole network of resistors.
3. You need wiring to connect the power source to the load or loads.
They are all necessary parts of a carburetor which allow it to perform properly.
-- power supply -- power-dissipating component -- connecting conductors
Simple parts of a circuit are switches, light bulb, battery and connecting wires.
complex circuit
It is a safety device. It is not an essential part of the circuit.
Battery, switch, wires, lightbulb, etc. Those are SOME parts of a circuit....
A circuit in which all parts are connected in a single loop
parallel
it can be either, depending on parts used in the circuit and their connections.
Simple parts of a circuit are switches, light bulb, battery and connecting wires.
It is often necessary to wire crossing
Biasing is necessary in a transistor circuit to keep the transistor working. Without proper biasing, the circuit will fail