# SCHEMATIC DIAGRAM GUIDELINE

• Engineer already developed  ways to control the flow of electricity for many useful

Purposes. Flow  of diagram with interconnection of wire is called schematics. The Schematic diagram is main part of Electronics Product.

An electronics Engineer who understands basic electronic theory can explain the following schematic.

• For  schematic diagrams use a set of standardized symbols to represent different component types.
• As per shown Schematic , the symbol next to the BT represents a Battery, the symbol next to the S represents a switch, and the one next to DS represents a display or a lamp. As per Schematic of theĀ  letters BT, S, and DS are labels that help identify the component, and these labels are called REFERENCE DESIGNATORS.

Anyone who knows how to interpret the schematic can build the circuit it represents by connecting of Battery, Switch and Lamp together with wire or any other form of conductive material.

SCHEMATIC DIAGRAM – According to drawing , The electrical connection of all components which have symbol with Reference Designators and functions of a specific circuit arrangement

• These are the most common symbols you will see on schematics, and the Reference Designate that are used to identify them.
• Note that some Reference Designators are used for more than one symbol. Even though there are

Separate symbols for “capacitors” and “polarized capacitors”, the reference designator for both of Them is C.

• Integrated Circuits, Modules (like power supplies) and Sub-Assemblies (like daughter boards) are

Usually drawn as a rectangle with a number of pins attached. Thousands of components share this Symbol style and the U reference designator. Many components have so many pins that the symbol

Has to be divided into multiple parts.

• In addition to Reference Designators, symbols are also assigned numbers to differentiate Components of the same type. For example, if we added more than one Resistor in Schematic, they will be Reference Designators R1, R2, R3, etc.
• This is not a complete set of symbols, but it should be enough to get you started. For example,

There are many types of transistors, but only two are shown here. As a circuit board designer you Probably won’t have to know the difference between them. For now, you just want to get a general Idea of what they look like.

Values and Attributes

• As per above schematic, there is not enough information to know what is intended. The Components are identified by a reference designator (the letters BT, S and DS), but there is no Information about what type or what size the components should be. Consider the fact that there Are many different types of batteries available, but nothing in the schematic above suggests which Battery would be best. The circuit shown above could be:
•  The simple flashlight with a size AA battery, or
• A 9V battery, a doorbell button and a buzzer, or
•  A 12V car battery, a rotary switch and a headlamp.
• Applying the same basic circuit to these different applications illustrates the fact that in the real world, a schematic must provide more information. A schematic must include ATTRIBUTES to insure that appropriate components are selected. The same resistor symbol can be used for thousands of different. kinds of resistors, so to be useful it must declare the VALUE, expressed in ohms. The ohm symbol is usually dropped because it is not available in all character sets, so a resistor with the number 100 next to it would be interpreted as “a hundred ohm resistor”. Other types of components are described with different terms; capacitors are differentiated by their value in farads (F), inductors are differentiated by their value in Henrys (H) Many additional attributes can be added to symbols (Power Ratings, Tolerances, etc.) to more tightly control the type of component needed for the design.

In addition to visible attributes for each symbol, many Computer-Aided Design (CAD) systems can also assign some unique attributes such as manufacturer part numbers, cost, revision levels or simulation data.