Capacitors

A capacitor is a component that stores an electrical charge. It consists of two plates separated by an insulator. The amount of capacitance is measured in Farads but as this is too large a unit for everyday electronics we use smaller units such as microfarads and smaller. Capacitors come in many types including electrolytic, polyster, polypropylene, ceramic, paper and mica. Measurement and Testing The...

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Resistor Combination

Resistors can be connected such parallel or series. Resistors are in series if they are connected in tandem and carry exactly the same current. Resistors are arranged in a chain, so the current has only one path to take. The current is the same through each resistor. The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors. Resistors...

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TYPES OF RESISTORS

Resistors are made in many forms, but all belong in either of two groups: fixed or variable. The relative sizes of all fixed and variable resistors change with the wattage (power) rating, increasing in size for increased wattage ratings in order to withstand the higher currents and dissipation losses. Fixed Resistors Resistors of this type are readily available in values ranging from...

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Measuring Voltage

Voltage is always referenced to something, usually a local ground. To measure a voltage, you will first connect the ‘common’ jack of the meter to the circuit common (i.e., breadboard ground). Next you will connect the meter’s ‘voltage’ jack to the point of interest. The meter will then tell you the voltage with respect to ground at this one point. When connecting things, it’s always a good idea to...

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Kirchhoff’s Law

In 1845, German physicist Gustav Kirchhoff first described two laws that became central to electrical engineering. The laws were generalized from the work of Georg Ohm. The laws can also be derived from Maxwell’s equations, but were developed prior to Maxwell’s work. Kirchhoff’s Current Law (KCL):         The algebraic sum of  the currents entering any node is zero...

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Multimeter

Multimeters allow measurement of voltage, current, and resistance. Multimeters may use analog or digital circuits—analog multimeters and digital multimeters. An analogue meter moves a needle along a scale. Switched range analogue multimeters are very cheap but are difficult for beginners to read accurately, especially on resistance scales. Most modern multimeters are digital. Digital meters give...

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OHM’S LAW

An excellent analogy for the simplest of electrical circuits is the water in a hose connected to a pressure valve. Think of the electrons in the copper wire as the water in the hose, the pressure valve as the applied voltage, and the size of the hose as the factor that determines the resistance. If the pressure valve is closed, the water simply sits in the hose without motion, much like the electrons...

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