How to Read a Schematic

Summary

This video script offers a beginner's guide to reading electronic schematics, explaining the use of specific symbols to represent components like batteries, resistors, switches, and LEDs. It clarifies the difference between a wiring diagram and a schematic, emphasizing the importance of understanding symbols and the representation of connections, including the use of ground symbols. The script also touches on the concept of polarized and non-polarized capacitors, and introduces a potentiometer for adjustable resistance. Viewers are directed to a webpage for more symbols and encouraged to explore related projects on the presenter's YouTube channel.

Takeaways

• 😀 A schematic is a diagram that uses specific symbols to represent electronic components and their connections, as opposed to a wiring diagram which uses pictures or photos of parts.
• 🔋 The symbol for a battery in a schematic is a longer line to represent the positive side, and additional lines for multiple cells.
• ⚡ The resistor is symbolized by a zigzag line in North America or a rectangle in the international standard.
• 🔑 The on/off switch is depicted as an open line when off and a different symbol when on.
• 💡 The LED symbol in a schematic includes arrows to indicate light emission, which is characteristic of a light-emitting diode.
• 🔗 Learning the symbols is crucial for understanding schematics, although there are many, only a few are commonly used.
• 🔄 Wires in a schematic can cross without connection, indicated by no dot at the intersection, or with a connection, indicated by a dot.
• 🌐 The ground symbol, representing earth ground and negative, is used to simplify wiring diagrams by connecting multiple lines to a single point.
• 🚗 Different types of grounds exist, such as chassis ground in cars, each with its unique symbol.
• ➡️ A diode allows current to flow in one direction only, with the arrow indicating the direction of conventional current flow.
• 🎚 A potentiometer, or variable resistor, is symbolized with an arrow pointing to it and is used for adjusting values, like volume in a radio.

Q & A

What is the main difference between a wiring diagram and a schematic?

A wiring diagram is a visual representation of a circuit using pictures or photos of the parts and colored lines, while a schematic uses specific symbols to represent components and is not always laid out like the final circuit.

What does the symbol for a battery represent in a schematic?

In a schematic, the symbol for a battery typically represents one battery cell, with multiple cells drawn together if the battery has more than one cell. The longer line indicates the positive side of the battery.

How is a resistor represented in a schematic in North America?

In North America, a resistor is represented by a zigzag line in a schematic.

What is the international standard symbol for a resistor?

The international standard symbol for a resistor is a rectangle.

What does the symbol for an on/off switch look like in a schematic?

The symbol for an on/off switch in a schematic is typically drawn as a diagonal line with a gap, indicating it is open or off. If it is closed or on, the gap would be filled.

What is the symbol for an LED in a schematic and why is it designed that way?

The symbol for an LED in a schematic is a diode symbol with arrows representing light being emitted from it. This design makes sense because LED stands for Light Emitting Diode.

How do you know if the lines in a schematic are connected or not?

In a schematic, if lines cross without a dot at the intersection, they are not connected. If a dot is present at the intersection, it indicates that the lines are connected.

What is the purpose of the ground symbol in a schematic?

The ground symbol in a schematic represents earth ground and is used to simplify the wiring by indicating where all the lines eventually end up, without having to draw all the lines to one ground symbol.

What is the difference between a polarized and a non-polarized capacitor in terms of their symbols in a schematic?

A polarized capacitor, like an electrolytic capacitor, is represented by a symbol with a plus or minus sign or a stripe on one side. A non-polarized capacitor is represented by two straight lines without any signs.

What is a potentiometer and how is it symbolized in a schematic?

A potentiometer is an adjustable resistor, used for example to adjust volume in a circuit. In a schematic, it is symbolized like a resistor with an arrow pointing to it, following the international standard of a rectangle for resistors.

What is the direction of conventional current flow in relation to the diode symbol in a schematic?

Conventional current flow is in the direction of the arrow in the diode symbol, which is opposite to the flow of negative electrons.

Outlines

00:00

📚 Introduction to Schematic Reading

The video script begins with an introduction to reading schematics for beginners in electronics. It clarifies the difference between a wiring diagram and a schematic, which uses specific symbols to represent components rather than a physical layout. The script introduces a simple circuit with a battery, resistor, switch, LED, and wires, explaining the schematic symbols for each component. It emphasizes learning the symbols as a key part of understanding schematics and touches on the representation of wiring, including how lines can cross without being connected and the use of a dot to indicate a connection.

🔌 Understanding Schematic Symbols and Wiring

This section delves deeper into the specifics of schematic symbols, explaining the symbols for batteries, resistors, switches, and LEDs. It also discusses how to interpret lines crossing in a schematic and the significance of dots at intersections to indicate actual connections. The script introduces the concept of grounding with different symbols for earth ground and chassis ground, explaining their use in simplifying wiring diagrams.

🔆 Exploring Diodes, Potentiometers, and Capacitors

The script continues with an explanation of diodes and their one-directional current flow, including the conventional current direction and how it's represented in schematics. It then introduces the potentiometer, a variable resistor symbolized with an arrow, and explains its use in adjusting, for example, the volume in a circuit. Additionally, the section covers capacitors, differentiating between polarized and non-polarized types, and their respective symbols in a schematic.

🛠️ Practical Applications and Additional Resources

The final part of the script provides practical applications of the concepts discussed, such as using a potentiometer to adjust LED brightness in a simple circuit and mentioning the presence of capacitors in more complex setups. It directs viewers to a webpage on the creator's website for more symbols and encourages further learning. The script also promotes the creator's YouTube channel for more educational content, including a video on building a crystal radio amplifier, a Joule thief circuit, and a music player based on a 555 timer chip, ending with a call to action for subscriptions, likes, and comments.

Keywords

💡schematic

A schematic is a visual representation of an electrical circuit using standardized symbols to represent components and connections. It is the primary tool for understanding, designing, and troubleshooting electronic circuits. In the video, the schematic is introduced as a complex diagram that, unlike a wiring diagram, uses specific symbols and may not reflect the physical layout of the final circuit.

💡wiring diagram

A wiring diagram is a type of diagram that shows the connections between electrical components using lines and often includes photographs or pictures of the parts. It is simpler and more straightforward than a schematic and is used to illustrate the physical layout of a circuit. The script contrasts wiring diagrams with schematics, emphasizing the schematic's use of symbols and abstract representation.

💡battery

A battery is a device that stores electrical energy and provides power to a circuit. In the context of the video, the battery is represented by a specific symbol in a schematic, indicating its positive and negative terminals. The script uses the battery as an example of how different components are symbolized in a schematic diagram.

💡resistor

A resistor is an electronic component that opposes the flow of electrical current in a circuit, providing a specific amount of resistance. The video explains that resistors are represented by a zigzag line in North America and a rectangle in the international standard. The script uses the resistor to illustrate the learning process of recognizing and understanding schematic symbols.

💡LED

An LED, or light-emitting diode, is a semiconductor device that emits light when an electrical current passes through it. In the script, the LED is shown as a symbol with arrows indicating the direction of light emission. The video uses the LED to demonstrate how components are symbolized in a schematic and how they function within a circuit.

💡switch

A switch is a device that breaks or makes a connection in a circuit, controlling the flow of electricity. The video describes the schematic symbol for an on/off switch and how it appears when it's open (off) or closed (on). The switch is a fundamental component in the simple circuit example provided in the script.

💡diode

A diode is an electronic component that allows current to flow in one direction only. The script explains the symbol for a diode and how it is represented in a schematic, with an arrow indicating the direction of conventional current flow. The diode is used to teach the concept of unidirectional current flow in electronic circuits.

💡potentiometer

A potentiometer is a type of resistor with a movable contact that allows for adjustment of the resistance in a circuit. The video describes the symbol for a potentiometer, which includes an arrow pointing to it, and how it can be used to adjust the volume in a crystal radio amplifier. The potentiometer is an example of a variable component in a schematic.

💡capacitor

A capacitor is a component that stores electrical energy in an electric field. The script distinguishes between polarized capacitors, which have a positive and negative side, and non-polarized capacitors. The video uses capacitor symbols to teach about the different types of capacitors and their representation in schematics.

💡ground

Ground, or earth ground, is a reference point in an electrical circuit that is used to establish a common voltage level. The video explains the use of the ground symbol in schematics to simplify wiring and indicates that all lines eventually connect to the ground. The script uses the concept of ground to illustrate how electrical circuits are completed.

💡chassis ground

A chassis ground is a specific type of ground where the negative side of a battery and many electrical components are connected to the vehicle's chassis. The script introduces the symbol for chassis ground and explains its use in automotive electrical systems. The concept of chassis ground is used to illustrate different grounding practices in various applications.

Highlights

Introduction to the basics of reading a schematic for beginners in electronics.

Explanation of the difference between a wiring diagram and a schematic.

Overview of a simple circuit with a battery, resistor, switch, LED, and wires.

Description of the schematic symbols for different components like batteries, resistors, and LEDs.

Importance of learning schematic symbols for understanding circuit diagrams.

Clarification on how lines in schematics represent wiring and the significance of crossed lines.

Use of a dot to indicate a connection where lines cross in a schematic.

Introduction to the concept of earth ground and its schematic symbol.

Different types of grounds, such as chassis ground in a car, and their symbols.

Explanation of diode function and its schematic symbol, including conventional current direction.

Introduction to the potentiometer and its schematic symbol for adjustable resistance.

Demonstration of replacing a fixed resistor with a potentiometer in a circuit.

Discussion on capacitors, including polarized and non-polarized types and their symbols.

Invitation to visit the webpage for more symbols and additional learning resources.

Promotion of the YouTube channel 'rimstarorg' for more electronics-related videos.

Encouragement to subscribe, like, and comment on the video for further engagement.

Transcripts

hi gang I'm gonna give you the basics on

how to read a schematic for anyone new

to electronics if your experience with

schematics and you have any helpful tips

for beginners please feel free to leave

them in the comments below what do I

mean by schematic to keep things simple

for people new to electronics often I'll

draw a circuit like this with little

pictures or photos of the parts and

different colored lines this is called a

wiring diagram however a schematic would

look like this drawn with specific

symbols and not always laid out like the

final circuit that's what you'll see

most of the time let's start with a very

simple circuit there are some batteries

a resistor an on/off switch and an LED

and of course they're also the wires

connecting it all together we flip the

switch to the on position and the LED

lights on here's the schematic for it

you can see that different symbols

represent different parts on the circuit

this is the symbol for a battery or a

one battery cell if the battery has more

than one cell then you'd simply have

more of them drawn together the longer

line is the positive side of the battery

most batteries have a marking on them

indicating which terminal is positive

and or negative in North America the

symbol for the resistor is a zigzag line

like this the international standard is

to draw it as a rectangle like this the

on/off switch is drawn like this here

it's drawn open or off if we're closed

or on then it would look like this the

symbol for the LED looks like this it's

a symbol for a diode but with arrows

representing light being emitted from it

that makes sense since LED stands for

light emitting diode so a big part of

learning to read schematics is learning

the symbols and though there are a lot

of them you mostly use only a handful

another part to schematics is the lines

representing the wiring the schematic

can get so complicated that lines have

to cross each other this happens with my

crystal radio amplifier

here's the schematic for it if the lines

cross each other like this or this or

this

then they're not connected if the lines

are supposed to be connected then a dot

will be drawn at the intersection there

is a way to simplify the lines and that

makes use of a symbol like this this

means earth ground and is negative

notice that all these lines eventually

end up at the earth ground and in fact

they do there are these wires in the

actual breadboard and here they are all

solder together in the back instead of

trying all those lines going to the one

ground symbol we can just draw in the

ground symbol wherever needed and it'll

be understood that all those lines end

up with the same ground there are the

types of grounds too for example in a

car the negative of the battery and the

negative of a lot of the electrical

components are connected to the cars

chassis that's called the chassis ground

and has this symbol this is a diode it

allows current to flow in one direction

only this direction the negative side is

this side if you're used to thinking in

terms of electrons which are negative

electrons flow in this direction against

the arrow conventional current is in the

opposite direction

since that's the flow of positive charge

so conventional current flows in the

direction of the arrow

notice that the line next to the arrow

corresponds to the line drawn near one

end of the actual diode this is a

resistor that you can adjust call the

potentiometer my crystal radio amplifier

I use it to adjust the volume its symbol

is the same as a resistor with a fixed

value like in our simple circuit but

with an arrow pointing to it remember

that in the international standard a

rectangle is used for the resistor so

the potentiometer looks like this we can

replace the fixed value resistor on our

simple circuit with potentiometer since

we're replacing just one resistor we

connect to the middle and one of the

ends and leave the other end unconnected

that allows us to adjust the brightness

of the light notice that this circuit

also has some capacitors this symbol is

for capacitors that have a positive side

and a negative side what are called

polarised capacitor

for example electrolytic capacitors are

polarized capacitors they usually have a

stripe drawn on one side like this or a

minus sign or both but not all

capacitors have positive and negative

sides the symbol here is for a non

polarized capacitor just two straight

lines these capacitors come in many

shapes and sizes and don't have any

minus signs on them and that should get

you started on reading schematics for

more symbols see this webpage on my

website well thanks for watching see my

youtube channel rimstarorg for more

videos like this that includes one

showing my crystal radio amplifier in

action along with step-by-step

instructions to make your own another

showing how to make a Joule thief

circuit that powers a compact

fluorescent light bulb and one showing

my music player based on a 555 timer

chip circuit and don't forget to

subscribe if you like these videos or

give a thumbs up leave a question or

comment below see you soon