ROBOTICS ENGINEERING | BASIC COMPONENTS
Please note that many aspects of working with electronic components and workshop equipment can be dangerous. This section is designed to provide a platform to help your teacher or supervisor guide you in learning. Incorrect use of equipment or mistakes made with live circuits can cause heat, fire, explosions and serious injuries. Always take care when doing projects and ensure adequate supervision by a qualified person and if needed and wear protective equipment.
SECTION 1 | LEDs
LEDs are a great way to start projects, start learning and start to build circuit control. If you can make a LED light then it is the same principle as making a motor spin, if you can control when the LED lights then you are at the first stage of being able to control the actions of a robot.
LEDs come in many sizes for the purpose of the information a 5mm LED will be used in pictures, information and Videos.
LEDs also come in different values and different colour LEDs of the same style often have different values. For example the Red LED in the picture below is 3v and 20mA and the Blue is 3V and 30mA.
LEDs have a positive and a negative side and will not work if you connect them the wrong way around. The long leg of the LED is the Anode which should be connected to the positive and the short leg of the LED is the Cathode and should be connect to the negative. Sometimes the legs may have been cut to the same length, you can still tell the negative because on the glass part of the LED the negative side has a flat surface – you will have to look close and careful to see this.
LEDs come in many sizes for the purpose of the information a 5mm LED will be used in pictures, information and Videos.
LEDs also come in different values and different colour LEDs of the same style often have different values. For example the Red LED in the picture below is 3v and 20mA and the Blue is 3V and 30mA.
LEDs have a positive and a negative side and will not work if you connect them the wrong way around. The long leg of the LED is the Anode which should be connected to the positive and the short leg of the LED is the Cathode and should be connect to the negative. Sometimes the legs may have been cut to the same length, you can still tell the negative because on the glass part of the LED the negative side has a flat surface – you will have to look close and careful to see this.
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For more information and some fun LEDs, projects can be found on the ELECTRONICS PROJECT page and the RASPBERRY PI projects page.
SECTION 2 | RESISTORS
Resistors are made of a semi conductive material; this means they will let current pass through them but because they are only semi conductive not all current will be able to pass through. Resistors have different values and depending on the value different amounts of current will be able to pass through.
Why do we need resistors?
Components such as LEDs are like kids at a party when it comes to consuming things, even when kids have eaten so much food they are full they often continue to eat until they are sick unless their parent stops them. Electrical components like LEDs act in a similar way, even though they have enough current to work, if the circuit continues to supply current the LED will to try to pull more current and eventually it will blow up, the resistor acts like the parent at the kid’s party and restricts the amount of current the LED is allowed.
Why do we need resistors?
Components such as LEDs are like kids at a party when it comes to consuming things, even when kids have eaten so much food they are full they often continue to eat until they are sick unless their parent stops them. Electrical components like LEDs act in a similar way, even though they have enough current to work, if the circuit continues to supply current the LED will to try to pull more current and eventually it will blow up, the resistor acts like the parent at the kid’s party and restricts the amount of current the LED is allowed.
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What are all the colour bands on a resistor?
Resistors have different values, this is different levels of resistance. If your power supply is very big compared to the component you are powering then you need a high value resistor. The colour band on a resistor represent the value of the resistor. There are many apps that you can download that quickly show values and help with resistors, the app used for projects on this site is called Resistor Code Calculator. Or a good website digikey |
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How do we calculate the value of the resistor we need to use?
Step 1: Spec Sheet
The first thing you’ll need is the spec sheet or datasheet of the component you are working with. This document provides critical information, including the operating voltage (V) and the current (I) required for the component to function properly. For example, an LED might have a forward voltage of 2V and a typical operating current of 20mA (0.02A).
Step 2: Know Your Power Supply
Secondly you should know the voltage and amps of the power supply.
Step 1: Spec Sheet
The first thing you’ll need is the spec sheet or datasheet of the component you are working with. This document provides critical information, including the operating voltage (V) and the current (I) required for the component to function properly. For example, an LED might have a forward voltage of 2V and a typical operating current of 20mA (0.02A).
Step 2: Know Your Power Supply
Secondly you should know the voltage and amps of the power supply.
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V = Voltage in Volts
I = Current in Amps R = Resistance in ohms For these projects the main calculation you will need is: Resistance = Voltage / Amps |
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Identify the voltage and current capabilities of the power supply you are using. This might be a 5V USB supply, a 9V battery, or another power source. Knowing the supply voltage (V) is essential, as you will be calculating how much resistance is needed to safely reduce the voltage or control the current to your component.
Step 3: Use Ohm’s Law
To calculate the required resistance, you will use Ohm's Law, which states:
V = I * R
Where:
R = V / I Where:
Step 4: Calculate the Resistance
For most basic projects, the main calculation you’ll use is the one for limiting current through a component like an LED.
Let’s go through an example:
V_difference = 5V - 2V = 3V
R = V_difference / I R = 3V / 0.02A = 150 ohms In this example, you would need a 150-ohm resistor to safely operate the LED in this circuit.
Step 5: Double-Check Power Ratings
It’s also important to check the power rating of the resistor. The power dissipated by the resistor is given by:
P = I^2 * R
For the example above:
P = (0.02A)^2 * 150 ohms = 0.06W Since this is quite a small value, a standard ¼ watt resistor would work perfectly in this case. Always choose a resistor with a power rating higher than what is calculated to ensure it doesn’t overheat.
Step 3: Use Ohm’s Law
To calculate the required resistance, you will use Ohm's Law, which states:
V = I * R
Where:
- V is voltage (in volts)
- I is current (in amps)
- R is resistance (in ohms)
R = V / I Where:
- R is the resistance you need,
- V is the voltage difference you need to account for (usually the difference between your power supply voltage and the component’s operating voltage),
- I is the current required by the component.
Step 4: Calculate the Resistance
For most basic projects, the main calculation you’ll use is the one for limiting current through a component like an LED.
Let’s go through an example:
- Suppose you're using a 5V power supply, and the LED you're using has a forward voltage of 2V and requires 20mA (0.02A) of current to operate.
- The voltage difference is:
V_difference = 5V - 2V = 3V
- The current is 0.02A.
- Using Ohm’s law, calculate the resistance:
R = V_difference / I R = 3V / 0.02A = 150 ohms In this example, you would need a 150-ohm resistor to safely operate the LED in this circuit.
Step 5: Double-Check Power Ratings
It’s also important to check the power rating of the resistor. The power dissipated by the resistor is given by:
P = I^2 * R
For the example above:
P = (0.02A)^2 * 150 ohms = 0.06W Since this is quite a small value, a standard ¼ watt resistor would work perfectly in this case. Always choose a resistor with a power rating higher than what is calculated to ensure it doesn’t overheat.
SECTION 3 | DIODES
What is a Diode?
A diode is a small electronic component that allows current to flow in only one direction. Think of it as a one-way valve for electricity. Diodes are important in circuits because they help control the flow of current, ensuring that electricity moves the way you want it to without damaging other parts of your circuit.
How Does a Diode Work?
A diode has two terminals, or ends:
Why Are Diodes Useful?
Diodes are used in circuits for various purposes, including:
Real-Life Example of a Diode in Use:
One common use of diodes is in LEDs (Light Emitting Diodes). LEDs are a special type of diode that emits light when current flows through it. Just like regular diodes, they allow current to flow in one direction only. If you connect an LED backward, it won’t light up!
Important Things to Know About Diodes:
Different Types of Diodes:
There are various types of diodes, each suited for specific uses. Here are two common ones:
How to Use a Diode in Your Projects:
When using a diode, always check its polarity (which end is the anode and which is the cathode). Place it in the circuit so that current flows from the anode to the cathode for proper operation. If you're using it for protection, place the diode in series with the component you’re protecting or across the power supply to prevent reverse current.
Diodes are a simple yet powerful component for controlling and protecting circuits. Understanding how they work will help you build better, safer projects!
A diode is a small electronic component that allows current to flow in only one direction. Think of it as a one-way valve for electricity. Diodes are important in circuits because they help control the flow of current, ensuring that electricity moves the way you want it to without damaging other parts of your circuit.
How Does a Diode Work?
A diode has two terminals, or ends:
- Anode (+): The positive side.
- Cathode (−): The negative side.
Why Are Diodes Useful?
Diodes are used in circuits for various purposes, including:
- Protecting Components from Reverse Polarity: Sometimes, you might accidentally connect a battery or power supply in the wrong direction, which could damage sensitive components. By placing a diode in the circuit, you can ensure that current only flows in the correct direction, protecting the components from reverse polarity damage.
- Rectification (Converting AC to DC): In many power supplies, diodes are used to convert alternating current (AC) to direct current (DC). This process is called rectification, and it is essential for running devices that require steady DC power from an AC source.
- Blocking Reverse Currents: Diodes can prevent current from flowing back into a circuit. For instance, in battery-powered circuits, a diode can stop the current from flowing back into the battery, preventing damage.
Real-Life Example of a Diode in Use:
One common use of diodes is in LEDs (Light Emitting Diodes). LEDs are a special type of diode that emits light when current flows through it. Just like regular diodes, they allow current to flow in one direction only. If you connect an LED backward, it won’t light up!
Important Things to Know About Diodes:
- Forward Voltage Drop: When a diode conducts electricity, it "uses up" a small amount of voltage, usually around 0.7V for standard diodes (silicon). This is known as the forward voltage drop. Make sure to account for this voltage drop in your circuit calculations.
- Reverse Breakdown Voltage: If a diode is subjected to too high a voltage in the reverse direction, it can break down and allow current to flow in the wrong direction. This is known as the reverse breakdown voltage, and it’s important to ensure your diode can handle the voltages in your circuit.
Different Types of Diodes:
There are various types of diodes, each suited for specific uses. Here are two common ones:
- Standard Diode: Allows current to flow in one direction and blocks it in the other.
- Zener Diode: Designed to allow current to flow in the reverse direction if the voltage exceeds a certain level. Zener diodes are often used in voltage regulation.
How to Use a Diode in Your Projects:
When using a diode, always check its polarity (which end is the anode and which is the cathode). Place it in the circuit so that current flows from the anode to the cathode for proper operation. If you're using it for protection, place the diode in series with the component you’re protecting or across the power supply to prevent reverse current.
Diodes are a simple yet powerful component for controlling and protecting circuits. Understanding how they work will help you build better, safer projects!
SECTION 4 | CAPACITORS
A capacitor is an electronic component that stores electrical energy, then releases it when needed. You can think of it like a small, temporary battery. However, unlike a battery, a capacitor can charge and discharge very quickly.
Capacitors are used in many electronic circuits to smooth out power fluctuations, filter signals, and store energy for short periods of time.
How Does a Capacitor Work?
A capacitor has two metal plates separated by an insulating material called a dielectric. When a voltage is applied to the capacitor, one plate stores positive charge, and the other plate stores negative charge. This creates an electric field between the plates, and energy is stored in that field.
The amount of energy a capacitor can store is measured in farads (F), but most capacitors used in electronics are much smaller and are measured in microfarads (µF), nanofarads (nF), or picofarads (pF).
Why Are Capacitors Useful?
Capacitors have many important roles in circuits. Here are some common uses:
How to Identify a Capacitor
Most capacitors are small, cylindrical, or disc-shaped components with two leads (wires) coming out of them. They often have markings indicating their capacitance value (how much energy they can store) and voltage rating (the maximum voltage they can handle).
Types of Capacitors
There are several types of capacitors, each designed for specific uses:
Important Things to Know About Capacitors
How to Use a Capacitor in Your Projects
To use a capacitor, you’ll typically connect it in parallel with the power supply or in series with components in a circuit. If you’re using a polarized capacitor like an electrolytic one, make sure to connect the positive and negative terminals correctly (positive lead to the positive side of the circuit, negative lead to the ground or negative side).
Real-Life Example of a Capacitor in Use
Capacitors are commonly used in power supplies to smooth out voltage. After converting AC to DC, capacitors store energy and fill in the gaps when the voltage fluctuates, providing a steady flow of current to sensitive components.
Capacitors are an essential building block in electronics, helping to stabilize, filter, and store energy in your circuits. Understanding how they work will help you design better projects and troubleshoot more effectively!
Capacitors are used in many electronic circuits to smooth out power fluctuations, filter signals, and store energy for short periods of time.
How Does a Capacitor Work?
A capacitor has two metal plates separated by an insulating material called a dielectric. When a voltage is applied to the capacitor, one plate stores positive charge, and the other plate stores negative charge. This creates an electric field between the plates, and energy is stored in that field.
The amount of energy a capacitor can store is measured in farads (F), but most capacitors used in electronics are much smaller and are measured in microfarads (µF), nanofarads (nF), or picofarads (pF).
Why Are Capacitors Useful?
Capacitors have many important roles in circuits. Here are some common uses:
- Smoothing Power Supply Voltages: In power supplies, capacitors help smooth out the variations in voltage. For example, after converting alternating current (AC) to direct current (DC), a capacitor is often used to reduce the "ripple" effect and provide a more stable DC voltage.
- Filtering Signals: Capacitors are often used in filtering applications. In audio or communication circuits, they can filter out unwanted noise by blocking certain frequencies while allowing others to pass through. This is called high-pass or low-pass filtering, depending on the frequency range you want to filter.
- Energy Storage: Capacitors can store energy and release it quickly when needed. This is useful in flash cameras, where the capacitor stores energy and releases it all at once to power the camera's flash.
- Timing Circuits: Capacitors can be combined with resistors to create timing circuits. These circuits control the timing of events, such as how long an LED stays on or how long it takes for a signal to change.
How to Identify a Capacitor
Most capacitors are small, cylindrical, or disc-shaped components with two leads (wires) coming out of them. They often have markings indicating their capacitance value (how much energy they can store) and voltage rating (the maximum voltage they can handle).
Types of Capacitors
There are several types of capacitors, each designed for specific uses:
- Electrolytic Capacitors:
- These capacitors have high capacitance values (e.g., 1 µF to thousands of µF).
- They are polarized, meaning they must be connected in the correct direction—positive to positive, negative to negative—otherwise they can be damaged.
- Commonly used for smoothing power supply voltages.
- Ceramic Capacitors:
- These are smaller capacitors with lower capacitance values (typically measured in pF or nF).
- They are non-polarized, meaning they can be connected in either direction.
- Often used for filtering and signal processing.
- Tantalum Capacitors:
- Similar to electrolytic capacitors but smaller in size with more stable performance.
- Polarized like electrolytic capacitors.
- Used in applications where size and stability are important.
Important Things to Know About Capacitors
- Capacitance (C): This is the amount of energy a capacitor can store, measured in farads (F). Larger capacitance values mean the capacitor can store more energy.
- Voltage Rating: Every capacitor has a maximum voltage it can safely handle. Exceeding this voltage can cause the capacitor to fail, sometimes catastrophically. Always make sure the voltage rating of the capacitor is higher than the voltage in your circuit.
- Charging and Discharging: Capacitors charge up when current flows into them and discharge when the stored energy is released. The time it takes to charge or discharge depends on the combination of the capacitor and any resistors in the circuit, a concept known as the RC time constant.
How to Use a Capacitor in Your Projects
To use a capacitor, you’ll typically connect it in parallel with the power supply or in series with components in a circuit. If you’re using a polarized capacitor like an electrolytic one, make sure to connect the positive and negative terminals correctly (positive lead to the positive side of the circuit, negative lead to the ground or negative side).
Real-Life Example of a Capacitor in Use
Capacitors are commonly used in power supplies to smooth out voltage. After converting AC to DC, capacitors store energy and fill in the gaps when the voltage fluctuates, providing a steady flow of current to sensitive components.
Capacitors are an essential building block in electronics, helping to stabilize, filter, and store energy in your circuits. Understanding how they work will help you design better projects and troubleshoot more effectively!
