ClassX Video Lessons Youtube Channel The Engineering Mindset LED Circuit Design – How to design LED circuits
In this article, we’re going to explore how LEDs, or light-emitting diodes, work and how to connect them safely in a circuit. LEDs are special components that light up when electricity flows through them. However, if too much electricity flows through, they can get damaged. Inside each LED is a tiny wire that can only handle a certain amount of current. If this limit is exceeded, the wire can break, and the LED will stop working.
To prevent LEDs from getting damaged, we use a component called a resistor. A resistor limits the amount of electricity that can flow through the circuit, which helps protect the LED. When electricity flows through a resistor, it generates heat. For example, if you have a circuit with 12 volts and 6 milliamps, the resistor can get very hot, reaching temperatures over 150 degrees Celsius!
Resistors can be placed on either side of the LED, but they are usually connected to the positive side. Think of a resistor like a traffic jam that slows down the flow of cars (or electrons, in this case) through the circuit.
LEDs only allow electricity to flow in one direction. The longer lead of the LED should be connected to the positive side of the circuit, and the shorter lead to the negative side. If you connect it the wrong way, the LED won’t light up. You can try this out with a simple setup using a red LED, a 9-volt battery, and different resistors.
When you measure the current flowing through the circuit with a multimeter, you should see a reading between 17 and 20 milliamps, depending on the components used. The total voltage drop across the circuit should equal the voltage of the battery. For instance, if you have a 9-volt battery, the LED might use up 2 volts, leaving 7 volts to be dropped across the resistor.
Each LED has a forward voltage, which is the minimum voltage needed for it to light up. This varies depending on the type of LED. Most standard LEDs are designed to handle a forward current of 20 milliamps. If the current is too low, the LED will be dim; if it’s too high, the LED might get damaged.
For example, if you have a 3-volt power supply and a red LED with a 2-volt drop, you’ll need a resistor to drop the remaining 1 volt. You can calculate the resistance needed using Ohm’s law. If you have a 9-volt battery and a yellow LED with a 2-volt drop, a 350-ohm resistor would keep the current at 20 milliamps.
When connecting multiple LEDs, you can arrange them in series or parallel. In a series connection, the voltage drops add up. In a parallel connection, each LED receives the same voltage. If you connect them in parallel, you can use one resistor for all LEDs or a separate resistor for each LED.
Resistor values can be combined to achieve the desired resistance. Resistors have color bands that indicate their values, and you can use charts to decode them. For more precise circuits, use resistors with lower tolerance ratings.
To learn more about electronics and electrical engineering, explore additional resources and videos. Keep experimenting and have fun with your LED projects!
Gather a red LED, a 9-volt battery, and a resistor. Connect them to create a simple circuit. Pay attention to the LED’s leads: the longer lead should connect to the positive side. Experiment with different resistor values to see how they affect the brightness of the LED.
Using multiple LEDs, try connecting them in series and then in parallel. Observe how the brightness changes in each configuration. Discuss why the brightness differs and how the voltage and current are distributed in each setup.
Choose an LED and a power supply. Calculate the resistor value needed to keep the current at 20 milliamps using Ohm’s Law. Verify your calculations by building the circuit and measuring the current with a multimeter.
Use a chart to decode the color bands on various resistors. Practice identifying the resistance values and tolerance ratings. Test your understanding by selecting the correct resistor for a given circuit requirement.
Construct a circuit with an LED and a resistor. Use a multimeter to measure the voltage drop across each component. Compare the total voltage drop to the power supply voltage and discuss your findings.
Here’s a sanitized version of the provided YouTube transcript, with unnecessary repetitions and informal language removed for clarity:
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In this video, we will discuss LEDs (light-emitting diodes), their operation, and how to connect them safely in a circuit. LEDs produce light when a current passes through them, but exceeding their voltage and current limits can destroy them. Inside an LED, there is a tiny wire that can only handle a specific amount of current. When an LED is destroyed, the wire can explode, which we can observe under a microscope.
To protect LEDs, we use a resistor. The resistor limits the flow of electrons, generating heat in the process. For example, at 12 volts and 6 milliamps, a resistor can reach temperatures over 150 degrees Celsius. Resistors can be placed on either side of the LED, but they are typically installed on the positive side. The resistor acts like a traffic jam, reducing the number of electrons flowing through the circuit.
It’s important to remember that LEDs only allow current to flow in one direction, with the longer lead connected to the positive side and the shorter lead to the negative side. If connected in reverse, the LED will not illuminate. You can test this with a simple circuit using a red LED, a 9-volt battery, and resistors of various values.
When measuring current through the circuit with a multimeter, you should see a reading between 17 and 20 milliamps, depending on the components used. The total voltage drop across the circuit should equal the battery voltage. For example, if the battery provides 9 volts, the voltage drop across the LED might be around 2 volts, and the remaining voltage drop across the resistor would be 7 volts.
Each component has a tolerance, meaning the measured values may differ slightly from the design values. The forward voltage is the minimum voltage required for the LED to illuminate, which varies by LED type. Most standard LEDs are rated for a forward current of 20 milliamps. If the current is too low, the LED will be dim; if too high, it may be destroyed.
For example, if we have a 3-volt supply and a red LED with a 2-volt drop, we need a resistor to drop the remaining 1 volt. The required resistance can be calculated using Ohm’s law. If we have a 9-volt battery and a yellow LED with a 2-volt drop, we would need a 350-ohm resistor to keep the current at 20 milliamps.
When connecting multiple LEDs, we can connect them in series or parallel. In series, the voltage drops add up, while in parallel, each LED receives the same voltage. If connecting in parallel, we can use one resistor for all LEDs or individual resistors for each LED.
Resistor values can be combined to achieve desired resistance. The color bands on resistors indicate their values, and we can use charts to decode them. For precision, we can use resistors with lower tolerance ratings.
To continue learning about electronics and electrical engineering, check out additional resources and videos.
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This version maintains the essential information while ensuring clarity and conciseness.
LED – A light-emitting diode, a semiconductor device that emits light when an electric current passes through it. – Example sentence: In our physics lab, we used an LED to demonstrate how electricity can produce light.
Circuit – A complete and closed path around which a circulating electric current can flow. – Example sentence: The teacher showed us how to build a simple circuit using a battery, wires, and a bulb.
Resistor – An electrical component that limits or regulates the flow of electrical current in an electronic circuit. – Example sentence: We added a resistor to the circuit to prevent the LED from burning out due to too much current.
Current – The flow of electric charge around a circuit, typically measured in amperes. – Example sentence: The ammeter was used to measure the current flowing through the circuit.
Voltage – The difference in electric potential between two points in a circuit, which causes current to flow, measured in volts. – Example sentence: The voltage across the battery was 9 volts, which was enough to power the small motor.
Electricity – A form of energy resulting from the existence of charged particles, such as electrons or protons, and used for power. – Example sentence: Understanding how electricity works is essential for designing and building electronic devices.
Components – Parts or elements that make up an electronic circuit, such as resistors, capacitors, and transistors. – Example sentence: We learned how to identify different components on a circuit board during our engineering class.
Series – A type of circuit configuration where components are connected end-to-end so that the current flows through each component sequentially. – Example sentence: In a series circuit, if one bulb burns out, the entire circuit stops working.
Parallel – A type of circuit configuration where components are connected across common points, allowing current to flow through multiple paths. – Example sentence: In a parallel circuit, each bulb operates independently, so if one goes out, the others remain lit.
Specifications – Detailed descriptions of the design and materials used to make a product, often including performance criteria. – Example sentence: The specifications for the new smartphone include a high-capacity battery and a fast processor.
