This chapter is divided into 6 parts. The first part deals with the Introduction. The second part covers electric circuits and schematic diagrams. The third part talks about electric current. The fourth part talks about electric voltage. The fifth part deals with resistance and Ohm's law. The sixth part discusses reference direction of voltage and current.

After completing this chapter, you will be able to: 1) identify series circuits, parallel circuits and series-parallel circuits 2) know how to determine the equivalent resistance for series, parallel and series-parallel resistive circuits 3) calculate the resistance, voltage, current and power for series, parallel and series-parallel resistive circuits 4) understand and apply the voltage-divider (VDR) and current-divider (CDR) rules 5) identify the wye (Y) and delta (Δ) circuits 6) know the method of wye (Y) and delta (Δ) conversions 7) apply the method of Δ-Y conversions to simplify bridge circuits 8) understand the method for measuring the unknown resistance of a balanced bridge circuit.

The scientists working in the field of electrical engineering have developed more simplified theorems to analyse these kinds of complex circuits (the com plicated circuit is also called the network). This chapter presents several theo rems useful for analysing such complex circuits or networks. These theorems include the superposition theorem, Thevenin's theorem, Norton's theorem, Millman's theorem and the substitution theorem. In electrical network analysis, the fundamental rules are still Ohm's law and Kirchhoff s laws.

After completing this chapter, you will be able to: 1) understand the first-order circuits and concepts of the step response and source-free response of the circuits 2) understand the initial conditions in the switching circuit 3) understand the concepts of the transient and steady states of RL and RC circuits 4) determine the charging/discharging process in an RC circuit 5) determine the energy storing/releasing process in an RL circuit 6) understand the concepts of time constants for RL and RC circuits 7) plot the voltages and currents verse time curves for RL and RC circuits 8) understand the relationship between the time constant and the charging/ discharging in an RC circuit 9) understand the relationship between the time constant and the energy storing/releasing in an RL circuit.

After completing this chapter, you will be able to: understand concepts and characteristics of the impedance and admittance of AC circuits; define the impedance and admittance of resistor R, inductor L and capacitor C; determine the impedance and admittance of series and parallel AC circuits; apply the voltage divider and current divider rules to AC circuits; apply KCL and KVL to AC circuits understand the concepts of instantaneous power, active power, reactive power, apparent power, power triangle and power factor; and apply the mesh analysis, node voltage analysis, superposition theorem and Thevinin's and Norton's theorems, etc. to analyse AC circuits.

This chapter will introduce the mutual inductance and transformer. A transformer is a device that is built based on the principle of mutual inductance and can be used to increase or decrease the voltage or current, and transfer electric energy from one circuit to another. It also can be used for impedance matching. Transformers have a very wide range of applications in power systems, tele communications, radio, instrumentation and many other electrical and electronics fields.