Electronics Engineering

parallel capacitors

2010-03-16T20:45:00.006+05:30

Q = Q1 + Q2

Q = V (C1+C2)

Q/V = C1+C2

C = C1 + C2

Capacitance

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Capacitance is typified by a parallel plate arrangement and is defined in terms of charge storage

F(farade)= Q(coulomb)/V(volt)

Characteristic of Parallel Circuit

2009-12-25T21:10:00.001+05:30

A Parallel Circuit has multiple paths or branches to ground. Therefore:

1. In the event of an open in the circuit in one of the branches, current will continue to flow through the remaining.
2. Each branch receives source voltage.
3. Current flow through each branch can be different.
4. The resistance of each branch can be different.

Parallel Circuit

2009-12-25T21:10:00.000+05:30

A parallel circuit has more than one path for current flow. The same voltage is applied across each branch. If the load resistance in each branch is the same, the current in each branch will be the same. If the load resistance in each branch is different, the current in each branch will be different. If one branch is broken, current will continue flowing to the other branches.

Characteristic of Series Circuits

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A Series Circuit has only one path to ground, so electrons must go through each component to get back to ground. All loads are placed in series.
Therefore:

1. An open in the circuit will disable the entire circuit.
2. The voltage divides (shared) between the loads.
3. The current flow is the same throughout the circuit.
4. The resistance of each load can be different.

Voltage Drop

A voltage drop is the amount of voltage or electrical pressure that is used or given up as electrons pass through a resistance (load). All voltage will be used up in the circuit. The sum of the voltage drops will equal source voltage. A voltage drop measurement is done by measuring the voltage before entering the load and the voltage as it leaves the load. The difference between these two voltage readings is the voltage drop.

Series Circuits

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A series circuit is the simplest circuit. The conductors, control and protection devices, loads, and power source are connected with only one path to ground for current flow. The resistance of each device can be different. The same amount of current will flow through each. The voltage across each will be different. If the path is broken, no current flows and no part of the circuit works. Christmas tree lights are a good example; when one light goes out the entire string stops working.

Types of Circuits

2009-12-06T11:47:00.001+05:30

Individual electrical circuits normally combine one or more resistance or load devices. The design of the automotive electrical circuit will determine which type of circuit is used. There are three basic types of circuits.

1.Series Circuit
2.Parallel Circuit
3.Series-Parallel Circuit

OHM'S LAW SYMBOL SHORTCUT

2009-12-04T18:55:00.004+05:30

Mathematical formulas can be difficult for many who don't use them regularly. Most people can remember a picture easier than a mathematical formula. By using the Ohms law symbol below, anyone can remember the correct formula to use. By knowing any two values you can figure out the third. Simply put your finger over the portion of the symbol you are trying to figure out and you have your formula.

E
-----------
I * R

Ohm's Law Formula

2009-11-30T22:44:00.000+05:30

When voltage is applied to an electrical circuit, current flows in the circuit. The following special relationship exists among the voltage, current and resistance within the circuit: the size of the current that flows in a circuit varies in proportion to the voltage which is applied to the circuit, and in inverse proportion to the resistance through which it must pass. This relationship is called Ohm's law, and can be expressed as follows:

E = I R

Voltage = Current x Resistance

E-Voltage applied to the circuit, in volts (V)
I-Current flowing in the circuit, in amperes (A)

R-Resistance in the circuit, in ohms

Introduction of the Electrical & Electronic Engineering

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ELECTRICITY BASICS

Electricity is the flow of electrons in a conductor and there are four quite intuitive quantities help to characterize it. Voltage, current, resistance and power

Voltage.

This term refers to the level of energy electrons have relative to some reference point (often called ground in a circuit). The higher the voltage, the more energy electrons have to do work as they travel through the circuit. In general, if two points are at a different voltage relative to each other, electricity will flow from one to the other if they are connected by something that conducts electricity. The unit of measurement of voltage is the Volt (V). As a sample of voltages our wall outlets at home (at least in the US) are 110V, the AA, C & D cells we buy at the corner store are all rated at 1.5V, and the electronics on Teleo Modules requires 5V.

Current.

This is an expression of how much charge is travelling through the conductor per second. The unit of measurement for current is the Amp (A). You can see that voltage and current are separate things: you can have a very small current at a very high voltage, a huge current at a very high voltage and so on.

Resistance.

Resistance is an expression of the degree to which electron flow will be impeded through a conductor. The unit is the Ohm . In simple circuits resistance determines the relation between voltage and current. At the extremes, a short piece of wire will have a resistance of nearly zero Ohms, while an air gap (for example in an open switch) has very large resistance (millions of Ohms). Intuitively a couple of relationships will hold: in a conductor, a voltage difference between the two ends will cause a current to flow. How much current will be determined by how much resistance the conductor offers. If there's less resistance more current will flow. In fact, given a power source of high enough capacity, if you half the resistance, you will double the current. Conversely, if you double the resistance, you will half the current.

Power.

The unit of power is the Watt. It's an expression of the overall energy consumed by a component. It is worked out by multiplying the voltage and the current together - P = VI. For example if a motor was running at 12V and the current it was drawing was 2A, the power it would be dissipating would be 24W

Ohm's Law

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Ohm's Law says;

The current in a circuit is directly proportional to the applied voltage and inversely proportional to the amount of resistance. This means that if the voltage goes up, the current flow will go up, and vice versa. Also, as the resistance goes up, the current goes down, and vice versa. Ohm's Law can be put to good use in electrical troubleshooting. But calculating precise values for voltage, current, and resistance is not always practical ... nor, really needed. A more practical, less time-consuming use of Ohm's Law would be to simply apply the concepts involved:

(I) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

(E) Current is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

(R) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a largeamount of current to flow. Resistance is measured in ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.