Week 3 Electrical Circuits and Components It’s a Radio! Electrical current comes in different forms depending on the source creating the voltage. Current that flows in only 1 direction all the time is called direct current (DC) Batteries and solar cells produce direct current Currently that regularly reverses direction is alternating current. generator Power company (Utility) A circuit is a complete path through which current can flow. Any break in the circuit will prevent the flow of electricity throughout the whole circuit. (open circuit) There are two basic types of pathways that can be set up for electric current to flow. A series circuit is connected so that there is only 1 pathway through which current can flow A parallel circuit is connected to provide each component with its own pathway. What is the name of a current That flows in only one direction? Direct current (DC) Are these bulbs connected in a series or a parallel circuit? Parallel What type of current is flowing through this circuit? Direct current Which of these circuits is a series circuit? A A B Some common Components used in Electronics It’s a Radio! Capacitors The function of a capacitor is to store and release electrical energy. A capacitor is made from two conducting surfaces separated by an insulating material, called the dielectric. The property of storing electric energy is called capacitance Capacitance is measured in farads. The purpose of the capacitor is to smooth out voltage changes. See videos about capacitors Inductors: Function is to store magnetic energy , An inductor is made from a coil of wire. The property of storing magnetic energy is called inductance Inductance is measured in henries. The purpose of the inductor is to smooth out current changes. Resistors: Function is to control the flow of current. Resistors have a certain specified resistance measured in ohms () Some resistors are variable, meaning the Resistance can be changed. This type of resistor is called a potentiometer, and is the type of component used as a volume control. Diodes allow current to flow in only 1 direction, meaning it can turn an ac current into a dc current by stopping the flow in the wrong direction. LED=Light Emitting Diode Transistors use voltage or current signals to control current flow. Transistors can be used as either an electronic switch or an amplifier. Gain is the term used that describes a transistor’s ability to amplify an signal. Circuit board showing component parts What electrical component is used to oppose the flow of current in a circuit? Resistor What electrical component stores energy in an electric field? Capacitor What type of electrical component consists of two or more conductive surfaces separated by an insulator? capacitor What type of electrical component stores energy in a magnetic field? Inductor What component prevents ac current from flowing in the “wrong” direction in a circuit? Diode Representations of components in a wiring diagram are schematic symbols. What is component 6 in the schematic above? Capacitor What is component 7 in the schematic shown above? Resistor Where is the diode located on the schematic diagram above? 5, 8 and 10 What component is shown at 4 in the schematic above? Transformer Where is the component located that is used to connect or disconnect this circuit? 3 Some components are used to prevent equipment damage or safety hazards such as fire or electrical shock due to equipment malfunction Fuses “blow” when excessive current melts a short length of metal. Fuses are not re-usable! Circuit breakers “trip” when the current overloads. They can be reset. Always replace a fuse or circuit breaker with the same size or model to avoid creating a safety hazard.