Electrical Schematic Code Diagrams

Electrical Schematic Diagrams

Style Presentation is a primary supplier of CAD assist services to power generation and distribution corporations in North The usa, and specializes in converting archives of electrical schematic diagrams(power plants, and so forth.) into electronic format, such as paper to CAD conversion, 2D to 3D conversion and redline alterations.

To meet the exacting requirements of the industry, our crew of CAD technicians realize the will need to adhere to sector norms:

All lines shall be drawn in accordance to pre-defined snap settings Provided the volume of drawings and the require for consistency, we extensively use LISP routines to meet top quality command specifications.All drawings that form a portion of essential infrastructure data (CII) shall be marked with a CII stamp.We mention all revision facts in the drawing Electrical Schematic Diagrams

We index all drawings and documents for electronic info management techniques (EDMS) functions

Electrical power generation and distribution organizations come across Design Presentation to be a expense powerful and time-sure solution to the previously mentioned requirements. Please use the our "Get A Quote" kind to submit your specifications. We would be happy to offer you with a free of charge quotation.

12v RELAY ON 6V SUPPLY

This circuit allows a 12v relay to operate on a 6v or 9v supply. Most 12v relays need about 12v to "pull-in" but will "hold" on about 6v. The 220u charges via the 2k2 and bottom diode. When an input above 1.5v is applied to the input of the circuit, both transistors are turned ON and the 5v across the electrolytic causes the negative end of the electro to go below the 0v rail by about 4.5v and this puts about 10v across the relay.

Alternatively you can rewind a 12v relay by removing about half the turns.

Join up what is left to the terminals. Replace the turns you took off, by connecting them in parallel with the original half, making sure the turns go the same way around 

LED FLASHER WITH ONE TRANSISTOR

LED FLASHER WITH ONE TRANSISTOR

This is a novel flasher circuit using a single driver transistor that takes its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED will not work. 

The flash rate cannot be altered by the brightness of the high-bright white LED can be adjusted by altering the 1k resistor across the 100u electrolytic to 4k7 or 10k. 

The 1k resistor discharges the 100u so that when the transistor turns on, the charging current into the 100u illuminates the white LED. 

If a 10k discharge resistor is used, the 100u is not fully discharged and the LED does not flash as bright. 

All the parts in the photo are in the same places as in the circuit diagram to make it easy to see how the parts are connected. 

AM FM Antenna Booster

AM FM Antenna Booster

This antenna booster circuit can be used to amplify the weak signal received by the antenna. Antenna for AM/FM is usually not tuned for the optimal dimension of 1/4 wavelength, since we prefer small portable size. This untuned antenna has very low gain, so the antenna booster circuit here is very helpful in getting better signal reception. Here is the schematic diagram of the circuit:

Use around 470uH coil for L1 if you use for AM frequency (700kHz-1.5MHz) and use around 20uH for SW or FM receiver. For short wave performance, using this antenna booster, you’ll get a strong signal as we get from a 20-30 feet antenna, with only a standard 18″ telescopic antenna and this booster circuit. The power supply should be bypassed by a 47nF capacitor to ground, at a point that should be chosen as close as possible to L1.

1.5V LED FLASHER CIRCUIT

1.5V LED FLASHER CIRCUIT

1.5V LED FLASHER CIRCUIT

AVERAGE CURRENT = 120uA

PEAK LED CURRENT = 20mA

4mS PULSE  1 FLASHE/SEC

APPROX. 6 MONTHS OPPERATION FROM N-CELL

APPROX. 12 MONTHS OPPERATION FROM AA CELL

DAVID JOHNSON AND ASSOCIATES

MINIATURE LED FLASHING CIRCUIT

1.5 VOLT CIRCUIT

Resistance & Resistor

What is resistance?

In the topic current we learnt that certain materials such as copper have many free electrons. Other materials have fewer free electrons and substances such as glass, rubber, mica have practically no free electron movement therefore making good insulators. Between the extremes of good conductors such as silver, copper and good insulators such as glass and rubber lay other conductors of reduced conducting ability, they "resist" the flow of electrons hence the term resistance.

The specific resistance of a conductor is the number of ohms in a 1' (305mm) long 0.001" dia round wire of that material.

Some examples on that basis are Silver = 9.75 ohms, Copper = 10.55 ohms, Nickel = 53.0 ohms and Nichrome = 660 ohms

From this information we can deduce that for a voltage applied to a piece of Nichrome wire , only around 10.55 / 660 = 0.016 of the amount of current will flow as opposed to the the current flowing in the same size copper wire.

The unit of resistance is the ohm and 1 ohm is considered the resistance of round copper wire, 0.001" diameter, 0.88" (22.35 mm) long at 32 deg F (0 deg C).
Resistance in series and parallel

It follows if two such pieces of wire were connected end to end (in series) then the resistance would be doubled, on the other hand if they were placed side by side (in parallel) then the resistance would be halved!

This is a most important lesson about resistance. Resistors in series add together as R1 + R2 + R3 + ..... While resistors in parallel reduce by 1 / (1 / R1 + 1 / R2 + 1 / R3 + .....)

Consider three resistors of 10, 22, and 47 ohms respectively. Added in series we get 10 + 22 + 47 = 79 ohms. While in parallel we would get 1 / (1 / 10 + 1 / 22 + 1 / 47) = 5.997 ohms.
Resistance and Power

Next we need to consider the power handling capability of our resistors. Resistors which are deliberately designed to handle and radiate large amounts of power are electric cooktops, ovens, radiators, electric jugs and toasters. These are all made to take advantage of power handling capabilities of certain materials.

From our topic on ohms law we learnt that P = I * I * R that is, power equals the current squared times the resistance. Consider our example above of the three resistors in series providing a total resistance of 79 ohms. If these resistors were placed across a 24 volt power supply then the amount of current flowing, from ohms law, is I = E / R = 24 / 79 = 0.304 amperes.

Using any of our power formulas we determine that 0.304 amperes flowing through our 79 ohm resistance dissipates a combined 7.3 watts of power! Worse, because our resistors are of unequal value the power distribution will be unequal with the greater dissipation in the largest resistor.

It follows as a fundamental rule in using resistors in electronic circuits that the resistor must be able to comfortably handle the power it will dissipate. A rule of thumb is to use a wattage rating of at least twice the expected dissipation.

Common resistors in use in electronics today come in power ratings of 0.25W, 0.5W, 1W and 5W. Other special types are available to order. Because of precision manufacturing processes it is possible to obtain resistors in the lower wattage ratings which are quite close in tolerance of their designated values. Typical of this type are the .25W range which exhibit a tolerance of plus / minus 2% of the value.

Resistors come in a range of values but the two most common are the E12 and E24 series. The E12 series comes in twelve values for every decade. The E24 series comes in twenty four values per decade.

E12 series - 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

E24 series - 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91

You will notice with the E12 values that each succeeding value falls within the plus / minus 10% of the previous values. This stems from the real old days when resistances were stated as within 20% tolerance (accuracy). Later values of plus / minus 5% tolerance led to the E24 range of resistance. Quite common today are 2% tolerance metal films types but for general purpose use we tend to stick to E12 values of resistance in either 1%, 2% or 5% tolerance.

Cost is the determining factor and many retailers now stock the 2% range of resistance as a standard to minimise stocking levels and also at reasonably low cost.

As examples of say the "22" types (red - red) from the E12 series we get 0.22, 2.2, 22, 220, 2,200, 22,000, 220,000 and 2,200,000 or eight decades of resistors.

In my opinion these ought to be referred to respectively as R22, 2R2, 22R, 220R, 2K2, 22K, 220K and 2M2. Here the R, K and M hold places where no decimal points are used to cause confusion.

Consider if I meant to write (in the old fashioned way) 2.2K in for a circuit value but forgot to type in the "K" so you just had 2.2, would the circuit work? No! How easy is it for you to read decimal points above.

Isn't 2K2 easier to see as meaning 2,200 ohms as against 2.2K? What if you didn't see the decimal point in 2.2K, couldn't it be taken to mean 22K or 22,000 ohms? Now you know why I prefer to use 2K2 or 22K or 22R - no confusion.
Resistance colour chart codes

Here in this large colour chart is the resistance colour code - learn the sequence forever -

BLACK, BROWN, RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE, SILVER, WHITE

I have accommodated two current colour banding of resistances - four band and five band resistance colour code. It should be pretty self explanatory I hope.


The five band code is more likely to be associated with the more precision 1% and 2% types. Your "garden variety" 5% general purpose types will be four band resistance codes.

INDUCTOR

 
 DEFINITION- An inductor is a passive electronic component that storesenergy in the form of a magnetic field. In its simplest form, an inductor consistsof a wire loop or coil. The inductance is directly proportional to the number ofturns in the coil. Inductance also depends on the radius of the coil and on the type of material around which the coil is wound.

For a given coil radius and number of turns, air coresresult in the least inductance. Materials such as wood, glass, and plastic - known as dielectric materials - are essentially the same as air for the purposes of inductor winding. Ferromagnetic substances such as iron, laminated iron, and powdered iron increase the inductance obtainable with a coil having a given number of turns. In some cases, this increase is on the order of thousands of times. The shape of the core is also significant. Toroidal (donut-shaped) cores provide more inductance, for a given core material andnumber of turns, than solenoidal (rod-shaped) cores.

The standard unit of inductance is the henry, abbreviatedH. This is a large unit. More common units are the microhenry, abbreviated µH (1 µH =10-6H) and the millihenry, abbreviated mH (1 mH =10-3 H). Occasionally, the nanohenry (nH) is used (1 nH = 10-9 H).

It is difficult to fabricate inductors onto integratedcircuit (IC) chips. Fortunately, resistors can be substituted for inductors in most microcircuit applications. In some cases, inductance can be simulated by simple electronic circuits using transistors, resistors, and capacitors fabricated onto ICchips.

Inductors are used with capacitors in various wirelesscommunications applications. An inductor connected in series or parallel with a capacitor can provide discrimination against unwanted signals. Large inductors are used in the power supplies of electronic equipment of all types, including computers and their peripherals. In these systems, the inductors help to smooth out the rectified utility AC, providing pure, battery-like DC.

CAPASITOR

Function

Capacitors store electric charge. They are used with resistors in timing circuits because it takes time for a capacitor to fill with charge. They are used to smooth varying DC supplies by acting as a reservoir of charge. They are also used in filter circuits because capacitors easily pass AC (changing) signals but they block DC (constant) signals.

Capacitance
This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values. 

Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico): 
µ means 10-6 (millionth), so 1000000µF = 1F 
n means 10-9 (thousand-millionth), so 1000nF = 1µF 
p means 10-12 (million-millionth), so 1000pF = 1nF 

Capacitor values can be very difficult to find because there are many types of capacitor with different labelling systems!
There are many types of capacitor but they can be split into two groups, polarised and unpolarised. Each group has its own circuit symbol.
Polarised capacitors (large values, 1µF +)

Examples: Circuit symbol: 

Electrolytic Capacitors
Electrolytic capacitors are polarised and they must be connected the correct way round, at least one of their leads will be marked + or -. They are not damaged by heat when soldering. 

There are two designs of electrolytic capacitors; axial where the leads are attached to each end (220µF in picture) and radial where both leads are at the same end (10µF in picture). Radial capacitors tend to be a little smaller and they stand upright on the circuit board. 

It is easy to find the value of electrolytic capacitors because they are clearly printed with their capacitance and voltage rating. The voltage rating can be quite low (6V for example) and it should always be checked when selecting an electrolytic capacitor. If the project parts list does not specify a voltage, choose a capacitor with a rating which is greater than the project's power supply voltage. 25V is a sensible minimum for most battery circuits. 

Tantalum Bead Capacitors
Tantalum bead capacitors are polarised and have low voltage ratings like electrolytic capacitors. They are expensive but very small, so they are used where a large capacitance is needed in a small size. 

Modern tantalum bead capacitors are printed with their capacitance, voltage and polarity in full. However older ones use a colour-code system which has two stripes (for the two digits) and a spot of colour for the number of zeros to give the value in µF. The standard colour code is used, but for the spot, grey is used to mean × 0.01 and white means × 0.1 so that values of less than 10µF can be shown. A third colour stripe near the leads shows the voltage (yellow 6.3V, black 10V, green 16V, blue 20V, grey 25V, white 30V, pink 35V). The positive (+) lead is to the right when the spot is facing you: 'when the spot is in sight, the positive is to the right'. 

For example: blue, grey, black spot means 68µF 
For example: blue, grey, white spot means 6.8µF 
For example: blue, grey, grey spot means 0.68µF

Polarised capacitors (large values, 1µF +) 

 Examples: 

 Circuit symbol:   

 Electrolytic capacitors are polarised and they must be connected the correct way round, at least one of their leads will be marked + or -. They are not damaged by heat when soldering. 

There are two designs of electrolytic capacitors; axial where the leads are attached to each end (220µF in picture) and radial where both leads are at the same end (10µF in picture). Radial capacitors tend to be a little smaller and they stand upright on the circuit board. 

It is easy to find the value of electrolytic capacitors because they are clearly printed with their capacitance and voltage rating. The voltage rating can be quite low (6V for example) and it should always be checked when selecting an electrolytic capacitor. If the project parts list does not specify a voltage, choose a capacitor with a rating which is greater than the project's power supply voltage. 25V is a sensible minimum for most battery circuits. 

Tantalum Bead Capacitors
Tantalum bead capacitors are polarised and have low voltage ratings like electrolytic capacitors. They are expensive but very small, so they are used where a large capacitance is needed in a small size. 

Modern tantalum bead capacitors are printed with their capacitance, voltage and polarity in full. However older ones use a colour-code system which has two stripes (for the two digits) and a spot of colour for the number of zeros to give the value in µF. The standard colour code is used, but for the spot, grey is used to mean × 0.01 and white means × 0.1 so that values of less than 10µF can be shown. A third colour stripe near the leads shows the voltage (yellow 6.3V, black 10V, green 16V, blue 20V, grey 25V, white 30V, pink 35V). The positive (+) lead is to the right when the spot is facing you: 'when the spot is in sight, the positive is to the right'. 

For example: blue, grey, black spot means 68µF 
For example: blue, grey, white spot means 6.8µF 
For example: blue, grey, grey spot means 0.68µF

 Unpolarised capacitors (small values, up to 1µF)
 Examples:   
 Circuit symbol: 

Small value capacitors are unpolarised and may be connected either way round. They are not damaged by heat when soldering, except for one unusual type (polystyrene). They have high voltage ratings of at least 50V, usually 250V or so. It can be difficult to find the values of these small capacitors because there are many types of them and several different labelling systems! 

Many small value capacitors have their value printed but without a multiplier, so you need to use experience to work out what the multiplier should be! 

For example 0.1 means 0.1µF = 100nF. 

Sometimes the multiplier is used in place of the decimal point: 
For example: 4n7 means 4.7nF. 

Capacitor Number Code
A number code is often used on small capacitors where printing is difficult: 
the 1st number is the 1st digit, 
the 2nd number is the 2nd digit, 
the 3rd number is the number of zeros to give the capacitance in pF. 
Ignore any letters - they just indicate tolerance and voltage rating. 
For example: 102 means 1000pF = 1nF (not 102pF!) 

For example: 472J means 4700pF = 4.7nF (J means 5% tolerance).

Capacitor Colour Code
A colour code was used on polyester capacitors for many years. It is now obsolete, but of course there are many still around. The colours should be read like the resistor code, the top three colour bands giving the value in pF. Ignore the 4th band (tolerance) and 5th band (voltage rating). 

For example: 

brown, black, orange means 10000pF = 10nF = 0.01µF. 



Note that there are no gaps between the colour bands, so 2 identical bands actually appear as a wide band. 

For example: 

wide red, yellow means 220nF = 0.22µF.

Colour Code
Colour Number
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Grey 8
White 9

Transistors

 INTRODUCTION - A transistor is a small electronic device that can cause changes in a large electrical output signal by small changes in a small input signal. That is, a weak input signal can be amplified (made stronger) by a transistor. For example, very weak radio signals in the air can be picked up by a wire antenna and processed by transistor amplifiers until they are strong enough to be heard by the human ear. A transistor consists of three layers of silicon or germanium semiconductor material. Impurities are added to each layer to create a specific electrical positive or negative charged behavior. "P" is for a positive charged layer and "N" is for a negative charged layer. Transistors are either NPN or PNP in the configuration of the layers. There is no particular difference here except the polarity of voltages that need to be applied to make the transistor operate. The weak input signal is applied to the center layer called the base and usually referenced to ground which is also connected to the bottom layer called the emitter. The larger output signal is take from the collector also referenced to ground and the emitter. Additional resistors and capacitors are required along with at least one DC power source to complete the transistor amplifier. You should have already studied the basic electricity and basic electronics sections of this web site and have a fairly good understanding of how resistors and capacitors effect electrical circuits. A typical transistor amplifier is shown below.

Dioda Semiconductor

The PN junction diode
Understanding the operation of the semiconductor diode is the basis for an understanding of all semiconductor devices. The diode is actually manufactured as a single piece of material but it is much easier to explain the operation if we imagine producing two separate pieces of N type and P type material and then "sticking" them together. 

Consider a piece of N type material. It contains mobile charge carriers in the form of free electrons. These electrons will be in motion due to thermal energy. (It is important to realise that this motion does not result in an electrical current because the motion is random and there is not net movement of charge from one area of the material to another. This is similar to the way that even in a perfectly still glass of water the individual molecules will be moving randomly on a microscopic scale.) The net result is that the random motion of the electrons results in them being evenly distributed throughout the N type material. In the P type material it is the positively charged holes that are mobile and for identical reasons to those previously described the holes are evenly distributed throughout the P type material.


Now consider what will happen if these two separate pieces of P and N type material are joined together. The random motion of the mobile electrons in the N type material and the holes in the P type material would tend to cause an even distribution of electrons and holes throughout the semiconductor. And in fact this is what begins to happen. 

Consider the electrons in the N type material. The electrons start to migrate across the junction of the two materials. When they cross into the P type material they recombine with the holes (ie they fill in the holes in the valence band by filling in the vacant electron positions around the trivalent donor atoms). This means that the number of holes near to the junction becomes depleted. Also as the electrons leave the previously neutral N type material a positive charge builds up at the junction. (This is because the positive charge from the nucleus of atoms near to the junction is now greater than the negative charge of the electrons in that region. This is due to the reduction in the number of electrons due to those which have moved across the junction.) 

Similarly as holes migrate from the P to N type material they recombine with electrons (the free electron from the pentavalent atoms completes the fourth covalent bond around the trivalent atom). This leaves a depletion of free electrons near the junction in the N type material. Also a negative charge builds up near the junction in the P type material due to the loss of positively charged holes. 

The net result is that the migration of electrons from N to P type material and the migration of holes from P to N has two effects. It results in a depletion of mobile charge carriers near the junction ( a depletion of electrons in the N type material and a depletion of holes in the P type material). This depletion layer is typically about 1 micrometre wide ( 1 millionth of a meter!). Also a voltage is produce across the junction which is called a barrier voltage. The N type material develops a positive charge close to the junction and the P type develops a negative charge. This prevents any further migration of mobile charge carriers. 

The effect of the barrier voltage
The positive charge at the N side of the junction repels any positively charged holes that would tend to migrate across the junction from the P type material. It also attracts free electrons and therefore to prevents them moving out of the N type material. Similarly the negative charge in the P type material close to the junction repels electrons which would tend to migrate from the N type material and it attracts the holes and prevents them moving out of the P type material. The migration of mobile charge carriers across the junction would stop when the barrier voltage had built up to a sufficient level to prevent any further migration. For Silicon this is about 0.6 to 0.7 volts for Germanium it is about 0.2 to 0.3 volts.

 

picture of DIODA