Instrumentation (AMME2700) 1 Instrumentation Dr. Xiaofeng Wu
Instrumentation (AMME2700) Atom and Electric Charge The charge of an electron Coulombs (C)
Instrumentation (AMME2700) Current and Voltage Current is the time rate of flow of electric charge past a given point The voltage is the work (energy) required to move a unit positive charge from – terminal to the + terminal.
Instrumentation (AMME2700) Basic Electrical Components a)Resistance b)Capacitance c)Inductance
Instrumentation (AMME2700) Ohm’s Law
Instrumentation (AMME2700) Power and Energy in Circuits
Instrumentation (AMME2700) Example 1 A resistor capable of handling safely 5W is to be placed across the terminals of a 10V voltage source. What range of resistances will not exceed the 5W limit?
Instrumentation (AMME2700) Kirchhoff’s Current Law Conservation of Charge Kirchhoff’s current law (KCL): At any instant the sum of the currents at a junction is zero.
Instrumentation (AMME2700) Kirchhoff’s Voltage Law Kirchhoff’s voltage law (KVL): At any instant in a closed loop, the sum of the voltages acting round the loop is zero.
Instrumentation (AMME2700) Example 2 Consider the circuit as shown a)Suppose that the resistance R 1 =8 Ω and R 2 =4 Ω. Find the current I and the voltage v. b)Suppose that i=2.25A and v=42V. Determine the resistance R 1 and R 2.