Introduction.
With connection in parallel, clams of generators & receivers are connected as on image #1. Thus all of clams connected in parallel are powered by the same voltage. Every of two-terminal circuits can be connected or disconnected independently of others.
(TODO: add image #1).
(... unfinished article, to be continued).
Thursday, December 31, 2015
Thursday, November 19, 2015
Simple Circuits: Connected in Series.
Introduction.
With connection in series, active two-terminal circuits (for example: generators), or passive (for example: resistors), are connected one after another.
Image #1: Two resistors connected in a serie.
Qualities of Connection in Series.
If we connect two resistors with connection in series to a power generator, the result of reading amperage before, in between & after resistors is always the same.
If we measure voltage on power generator's clams & on each of resitors as well, we'll notice that voltages on each of resistors are lesser than voltage of a power generator.
With a connection in series, on each of the resistors only part of voltage is lost. Whole voltage is spread across all of the resistors.
Sum of all voltages in a loop shown on Image #1, with direction considered, is totalling 0 (2nd Kirchoff's Law).
U - U2 - U1 = 0.
U = U1 + U2 + ...
This means that algebraic sum of all generators' voltages is equal to sum of all voltage losses on receivers.
If we measure (with ohmmeter) resistance of each of resistors & resistance of the whole circuit, we'll notice that resistance of whole circuit is equal to sum of resistances of each of resistors.
Current flowing through total resistance of whole circuit has the same intensity (amperage) as the current flowing through resistors connected in series.
R = R1 + R2 + ...
If individual resistors are equal, then with n resistors, total resistance is:
R = n · R1
On greater resistance there's greater voltage loss.
With connection in series, individual voltage drops are proportional to appropriate resistances.
U - generator's voltage;
U1, U2, ... - voltage drops;
R - total resistance;
R1, R2, ... - individual resistors;
Elements are connected in series when allowed voltage of individual element is smaller than generator's voltage.
Additional series-connected resistors.
Receiver (load) can be connected to a voltage greater than it's rated voltage if we add additional series-connected resistor(s). This resistor must be selected appropriately, to contain excess of a voltage & to survive the rated voltage of the generator.
Let's connect in series a light bulb 6V/0.3A with a generator with voltage of 24V. Let's use a resistor with appropriate resistance, to let it contain a voltage of 18V.
Image #2: A circuit with a resistor in a series-connection.
Voltage loss on leads.
In every circuit there are connected in series:
- power lead,
- receiver (load),
- return lead.
Because leads have a certain resistance Rl, with every receiver connection we have resistors connected in series.
Voltage loss on leads lowers receiver's (load's) voltage.
If we connect a light bulb to accumulator with a very long lead & if we measure voltage on a generator as well as a voltage on receiver (on load), we'll notice that a voltage on receiver (load) is lower than voltage on accumulator (generator). This is shown on image #3.
Image #3: A Practical Circuit, considering all of voltage losses.
If we'll connect in series to a first light bulb another a light bulb, voltage on receiver will be lower. Greater current's intensity (amperage) causes greater voltage loss in leads.
Voltage loss in leads is a cause for energy loss, that is transformed into heat. That's why it should be as small as possible. It's often given as a percentage of rated voltage.
Example #1:
Let's calculate a voltage loss in leads with a resistance of Rl = 2Ω connecting a light bulb 4,5V/1A with an accumulator.
ΔU = I · Rl = 1 A · 2 Ω = 2 V.
With connection in series, active two-terminal circuits (for example: generators), or passive (for example: resistors), are connected one after another.
Image #1: Two resistors connected in a serie.
Qualities of Connection in Series.
If we connect two resistors with connection in series to a power generator, the result of reading amperage before, in between & after resistors is always the same.
With connection in series, the amperage in each of two-terminal circuits is always the same. |
If we measure voltage on power generator's clams & on each of resitors as well, we'll notice that voltages on each of resistors are lesser than voltage of a power generator.
With a connection in series, on each of the resistors only part of voltage is lost. Whole voltage is spread across all of the resistors.
With connection in series, sum of voltage losses (voltage drops) in resistors is equal to power generator's voltage. |
Sum of all voltages in a loop shown on Image #1, with direction considered, is totalling 0 (2nd Kirchoff's Law).
This means that algebraic sum of all generators' voltages is equal to sum of all voltage losses on receivers.
If we measure (with ohmmeter) resistance of each of resistors & resistance of the whole circuit, we'll notice that resistance of whole circuit is equal to sum of resistances of each of resistors.
With connection in series, total resistance of whole circuit is equal to sum of individual resistances of each of particular resistors. |
Current flowing through total resistance of whole circuit has the same intensity (amperage) as the current flowing through resistors connected in series.
If individual resistors are equal, then with n resistors, total resistance is:
On greater resistance there's greater voltage loss.
With connection in series, individual voltage drops are proportional to appropriate resistances.
| U1 | R1 | U1 | R1 | |||
| = | = | |||||
| U | R | U2 | R2 |
U - generator's voltage;
U1, U2, ... - voltage drops;
R - total resistance;
R1, R2, ... - individual resistors;
Elements are connected in series when allowed voltage of individual element is smaller than generator's voltage.
Additional series-connected resistors.
Receiver (load) can be connected to a voltage greater than it's rated voltage if we add additional series-connected resistor(s). This resistor must be selected appropriately, to contain excess of a voltage & to survive the rated voltage of the generator.
Let's connect in series a light bulb 6V/0.3A with a generator with voltage of 24V. Let's use a resistor with appropriate resistance, to let it contain a voltage of 18V.
Image #2: A circuit with a resistor in a series-connection.
Voltage loss on leads.
In every circuit there are connected in series:
- power lead,
- receiver (load),
- return lead.
Because leads have a certain resistance Rl, with every receiver connection we have resistors connected in series.
Voltage loss on leads lowers receiver's (load's) voltage.
If we connect a light bulb to accumulator with a very long lead & if we measure voltage on a generator as well as a voltage on receiver (on load), we'll notice that a voltage on receiver (load) is lower than voltage on accumulator (generator). This is shown on image #3.
Image #3: A Practical Circuit, considering all of voltage losses.
ΔU = U1 - U2 | ΔU = I · Rl | |||
ΔU - voltage loss on leads. U1 - voltage loss on lead's beginning part. U2 - voltage loss on lead's ending part. I - current's intensity (amperage). Rl - lead's resistance. | ||||
On every lead through which the current flows, there's a voltage loss. |
If we'll connect in series to a first light bulb another a light bulb, voltage on receiver will be lower. Greater current's intensity (amperage) causes greater voltage loss in leads.
Voltage loss in leads is greater if the intensity (amperage) of the current is greater. Leads' greater resistance also causes greater voltage loss. |
Voltage loss in leads is a cause for energy loss, that is transformed into heat. That's why it should be as small as possible. It's often given as a percentage of rated voltage.
Example #1:
Let's calculate a voltage loss in leads with a resistance of Rl = 2Ω connecting a light bulb 4,5V/1A with an accumulator.
Wednesday, November 18, 2015
Simple Circuits: Arrow Notations.
Active & passive elements.
In electric circuits, there are active & passive elements:
- active element might be accumulator during power discharge,
- passive element might be accumulator during power charging.
Arrow notations.
Energy Flow.
On diagrams, arrows' directions mean positive direction of current's flow.
- positive current is the current flowing in direction of the positive flow, as noted with arrows,
- negative current is the current flowing in opposite direction of the positive flow, as noted with arrows.
Electric Current Arrow's Direction.
Reference arrow shows which of current's directions is positive. If electric current's direction & refernce arrow's direction are same, we have positive current. With opposite directions, we have negative current.
Voltage Arrow's Direction.
In a case of a voltage, reference arrows are drawn as arcs or straight lines that join points between which they show voltage.
Arrow's point shows positive voltage.
Two-Port Network with shown Electric Current's & Voltage's directions.
Direction of adding voltages can be shown by using indexes for voltage symbols. Positive direction of voltage is then counted starting from place marked by first-indexed symbol.
Two-Port Networks are energy converters that have two clamps at entering current side & two clamps at emerging current side. Current's arrows are drawn as to have them entering a Two-Port Network (it's marking system for a receiver device).
In electric circuits, there are active & passive elements:
- active element might be accumulator during power discharge,
- passive element might be accumulator during power charging.
Arrow notations.
Energy Flow.
On diagrams, arrows' directions mean positive direction of current's flow.
- positive current is the current flowing in direction of the positive flow, as noted with arrows,
- negative current is the current flowing in opposite direction of the positive flow, as noted with arrows.
Electric Current Arrow's Direction.
Reference arrow shows which of current's directions is positive. If electric current's direction & refernce arrow's direction are same, we have positive current. With opposite directions, we have negative current.
Voltage Arrow's Direction.
In a case of a voltage, reference arrows are drawn as arcs or straight lines that join points between which they show voltage.
Arrow's point shows positive voltage.
Two-Port Network with shown Electric Current's & Voltage's directions.
Direction of adding voltages can be shown by using indexes for voltage symbols. Positive direction of voltage is then counted starting from place marked by first-indexed symbol.
Two-Port Networks are energy converters that have two clamps at entering current side & two clamps at emerging current side. Current's arrows are drawn as to have them entering a Two-Port Network (it's marking system for a receiver device).
States of Matter.
Different States of Matter.
In physics, a state of matter is one of the distinct forms that matter takes on.
Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.
Many other states are known, such as Bose–Einstein condensates and neutron-degenerate matter, but these only occur in extreme situations such as ultra cold or ultra dense matter.
Other states, such as quark–gluon plasmas, are believed to be possible but remain theoretical for now.
Solid.
In a solid the particles (ions, atoms or molecules) are closely packed together.
The forces between particles are strong so that the particles cannot move freely but can only vibrate.
As a result, a solid has a stable, definite shape, and a definite volume.
Solids can only change their shape by force, as when broken or cut.
Liquid.
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure.
The volume is definite if the temperature and pressure are constant.
Gas.
A gas is a compressible fluid.
Not only will a gas conform to the shape of its container but it will also expand to fill the container.
Plasma.
Like a gas, plasma does not have definite shape or volume.
Unlike gases, plasmas are electrically conductive, produce magnetic fields and electric currents, and respond strongly to electromagnetic forces.
Positively charged nuclei swim in a "sea" of freely-moving disassociated electrons, similar to the way such charges exist in conductive metal.
In fact it is this electron "sea" that allows matter in the plasma state to conduct electricity.
In physics, a state of matter is one of the distinct forms that matter takes on.
Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.
Many other states are known, such as Bose–Einstein condensates and neutron-degenerate matter, but these only occur in extreme situations such as ultra cold or ultra dense matter.
Other states, such as quark–gluon plasmas, are believed to be possible but remain theoretical for now.
Solid.
In a solid the particles (ions, atoms or molecules) are closely packed together.
The forces between particles are strong so that the particles cannot move freely but can only vibrate.
As a result, a solid has a stable, definite shape, and a definite volume.
Solids can only change their shape by force, as when broken or cut.
Liquid.
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure.
The volume is definite if the temperature and pressure are constant.
Gas.
A gas is a compressible fluid.
Not only will a gas conform to the shape of its container but it will also expand to fill the container.
Plasma.
Like a gas, plasma does not have definite shape or volume.
Unlike gases, plasmas are electrically conductive, produce magnetic fields and electric currents, and respond strongly to electromagnetic forces.
Positively charged nuclei swim in a "sea" of freely-moving disassociated electrons, similar to the way such charges exist in conductive metal.
In fact it is this electron "sea" that allows matter in the plasma state to conduct electricity.
Tuesday, November 17, 2015
Energy & Matter.
Energy & Matter.
i read that Matter is an Energy Form.
Matter is made of Atoms.
Energy has many forms, is also made of Atoms & Free Electrons.
Energy Forms include:
- Potential Energy,
- Kinetic Energy,
- Chemical Energy,
- Mass Energy, as expressed in Einstein's famous equation: E = mc2,
- ...
Atoms & Free Electrons.
Atoms are made of Nucleus & Electrons orbiting around Nuclei.
Nucleus is made of Protons & Neutrons.
Protons give atom a positive charge, electrons give negative charge - when these neutralize each other, atom's charge is zero, a neutral charge.
An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge.
Free electron is an electron that is not attached to an atom or ion or molecule but is free to move under the influence of an electric field.
Atoms & Molecules.
An atom is smallest particle in an element that has the properties of the element. It is not possible to breakdown the atom further retaining the properties of the element.
Molecules are formed by the combination of two or more atoms. Unlike atoms, molecules can be subdivided to individual atoms. The atoms are bonded together in a molecule.
Physical Values.
Atom's mass ranges from 1.67 × 10−27 to 4.52 × 10−25 kg.
Atoms' size range from 0.1 to 0.5 nanometers in width (1 nm = 10-9 m).
Electron's mass is 9.10938291(40)×10−31 kg.
Electron's charge, Elementary Negative Charge, is equal to approximately: -1.6021766208(98)×10−19 coulombs.
Proton's mass is approximately 1.672621777(74)×10−27 kg.
Proton's charge is also Elementary Charge, Elementary Positive Charge, is equal to approximately 1.6021766208(98)×10−19 coulombs, a negation of electron's charge.
Neutron's mass is approximately 1.674927471(21)×10−27 kg.
Neutron's charge is 0.
it's hard to define subatomic particle's sizes in terms of 'balls with size'.
Electron size depends on how we perceive atom, if it's a 'small ball of energy', then it's approximately 1 femtometer (1 fm = 10-15 m).
i read that Matter is an Energy Form.
Matter is made of Atoms.
Energy has many forms, is also made of Atoms & Free Electrons.
Energy Forms include:
- Potential Energy,
- Kinetic Energy,
- Chemical Energy,
- Mass Energy, as expressed in Einstein's famous equation: E = mc2,
- ...
Atoms & Free Electrons.
Atoms are made of Nucleus & Electrons orbiting around Nuclei.
Nucleus is made of Protons & Neutrons.
Protons give atom a positive charge, electrons give negative charge - when these neutralize each other, atom's charge is zero, a neutral charge.
An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge.
Free electron is an electron that is not attached to an atom or ion or molecule but is free to move under the influence of an electric field.
Atoms & Molecules.
An atom is smallest particle in an element that has the properties of the element. It is not possible to breakdown the atom further retaining the properties of the element.
Molecules are formed by the combination of two or more atoms. Unlike atoms, molecules can be subdivided to individual atoms. The atoms are bonded together in a molecule.
Physical Values.
Atom's mass ranges from 1.67 × 10−27 to 4.52 × 10−25 kg.
Atoms' size range from 0.1 to 0.5 nanometers in width (1 nm = 10-9 m).
Electron's mass is 9.10938291(40)×10−31 kg.
Electron's charge, Elementary Negative Charge, is equal to approximately: -1.6021766208(98)×10−19 coulombs.
Proton's mass is approximately 1.672621777(74)×10−27 kg.
Proton's charge is also Elementary Charge, Elementary Positive Charge, is equal to approximately 1.6021766208(98)×10−19 coulombs, a negation of electron's charge.
Neutron's mass is approximately 1.674927471(21)×10−27 kg.
Neutron's charge is 0.
it's hard to define subatomic particle's sizes in terms of 'balls with size'.
Electron size depends on how we perceive atom, if it's a 'small ball of energy', then it's approximately 1 femtometer (1 fm = 10-15 m).
Monday, November 16, 2015
Resistors.
Resistors,
(resistors can look differently as well).
Definition.
A resistor is an electrical component that implements electrical resistance as a circuit element.
When choosing a resistor, four factors can be considered:
- value in Ohms (Ω),
- tolerance, for example: +/- 5%,
- power rate, maximum power which can be developed in a resistor without occuring damage by overheating,
- stability, ability to keep the same value with changes of temperature & with age.
Resistor Types.
- Fixed Resistors.
With fixed resistance & tolerance.
- Variable resistors.
Their resistance can be set, they also have tolerance - more or less precise.
- NTC Thermistors.
Negative Temperature Coefficient Resistors. Their resistance lowers with temperature's rise.
Usually their resistance is shown for temperature of 20 oC.
There are thermistors that are self-heated by an electric current's flow, so resistance depends also on electric current.
There are also thermistors through which small enough current is flowing, so the heat from the electricity is neglient & only outside heating counts as far as resistance is considered.
- PTC Thermistors.
Positive Temperature Coefficient Resistors. Their resistance rises with temperature's rise.
Most PTC thermistors are of the 'switching' type, which means that their resistance rises suddenly at a certain critical temperature.
- Varistors.
Also called VDR - Voltage Dependent Resistors.
Their resistance lowers strongly as Voltage rises.
Electric Current Density.
Electric current's density J depends on electric current's intensity I measured in (A) & on conductor wire's gauge S measured in mm2.
It is described by a physical formula:
J = I / S,
where:
- J is electric current's density, measured in A / mm2,
- I is electric current's intensity, measured in A,
- S is conductor wire's gauge, measured in mm2.
As electrons flow between two points with different electric potential (amount of electrons & positrons in an atom), physical medium resists their flow & gets heated.
Amount of heat depends on:
- conductor wire's gauge, measured in mm2 - in thinner conductor wires electrons flow faster & there's more heat,
- electric intensity - the more amperes the more heat,
- conductor wire's material - the more resistance the more heat.
it's all not so simple outside wired circuits, however.
It is described by a physical formula:
J = I / S,
where:
- J is electric current's density, measured in A / mm2,
- I is electric current's intensity, measured in A,
- S is conductor wire's gauge, measured in mm2.
As electrons flow between two points with different electric potential (amount of electrons & positrons in an atom), physical medium resists their flow & gets heated.
Amount of heat depends on:
- conductor wire's gauge, measured in mm2 - in thinner conductor wires electrons flow faster & there's more heat,
- electric intensity - the more amperes the more heat,
- conductor wire's material - the more resistance the more heat.
it's all not so simple outside wired circuits, however.
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