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Unformatted text preview: EE1002 Introduction to Circuits and Systems Double‐subscript notation for currents The two ends of a circuit element be named as a and b. Then the current in the element is either from a to b as Iab, or from b to a as Iba and Iab, =‐ Iba. Voltages Voltage is a measure of the energy transferred per unit charge when charge moves from one point in an electrical circuit to a second point. The units of voltage are volts (V), which is equivalent to Joules/Coulomb (J/C). Voltage is measured across an electrical element (i.e. between two ends of an element), where are current is a measure of the rate of charge flow through the element. Voltage has polarity (‐ and +). Positive terminal is at a higher energy level than the negative. If positive charge enters the positive polarity and exits the negative polarity, then the charge looses energy in the element (the element absorbs energy). When positive charge enters the negative terminal and exits at the positive terminal, then the charge absorbs energy from the element. Reference polarity Similar to the reference direction for current, there is the concept of reference polarity for voltages. The actual dire...
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- Winter '14