![]() ![]() If you are new here, then look at previous tutorials where you can learn timers, blinking LED, interfacing LCD etc. We have come up all the way from installing MPLABX to using a LCD with PIC MCU. This configuration is shown below.This is our 8th tutorial of Learning PIC microcontrollers using MPLAB and XC8. Using one 360 ohm resistor for every connected segment will ensure that all segments are supplied by approximately 25 mA. However, connecting more segments will reduce the current flowing through the LEDs until the segments will barely light up. Alternate Configurationsīy following the instructions above, you will be able to successfully light 3-4 7-segment displays without significant brightness loss. In this case, since the triangle of diode ‘a’ is pointing down, we can make the current flow down by connecting the positive end of the battery to ‘3,8’ and the negative end of the battery to ‘7’. If current isn’t flowing, or is flowing in the opposite ( reverse) direction of the triangle, the diode will be off. To turn a diode on, you need to make sure current is flowing through the diode in the direction the triangle is pointing (called the forward direction). However, if we reversed the battery connections, nothing would turn on. The direction in which the triangle is pointing changes how the diode works. If we were to connect the positive end of the battery to the line labelled ‘3,8’ and the negative end of the battery to the line labelled ‘7’, the LED ‘a’ would turn on. You can add electrical tape to the connection for stability.Īs you can see in the block diagram, a diode is shown as a triangle and a line. Solder a resistor to the positive lead of the battery clip. ![]() ![]() An alternate configuration, using one 360+ ohm resistor for each segment lit up, requires more resistors but does not require soldering and will not result in the loss of segment brightness.ġ. This will ensure the maximum supplied current is 25 mA, but will decrease the brightness of the LEDs as you add more segments. The easiest way to do so, described in this section of the activity, is to solder a 360+ ohm resistor to the positive lead of the battery clip. There are multiple ways to ensure that the current won’t exceed the maximum for your device. The maximum current rating and the connections inside different 7-segment displays may be different, and not using the devices correctly can “burn out” an LED (it is unlikely that the 7-segment will actually become hot, but the LED inside the segment can become unusable)Ī note on resistors: The 360+ ohm resistor used in this activity is chosen to limit the supplied current from the battery to a maximum of 25 mA, which is the maximum current for the device we are using. It is important to know whether the device is common anode (like the ones we are using) or common cathode. Adult supervision should be used to look up the type of 7-segment display you are using on the internet.Adult supervision needed for soldering.This will short the battery (the battery will heat up and could become dangerous). Be careful not to let the wire leads from the battery touch each other.Any resistor value between 360-500 ohms will work for this activity. There are a few different pin configurations – we like these ones (#160-1575-5-ND) from DigiKey. Some jumper wires, such as these ones from Digikey (#377-2093-ND) that are easy to use with a breadboard.If you are not familiar with how a breadboard works, this is a useful introduction. You can find most supplies from your local electronics stores or online. LEDs are really fun to learn how to use – if you want to learn more about how the LEDs inside of a 7-segment display work, you can find more information at the bottom of this page. ![]() This activity introduces how to use a 7-segment display using only a battery, a breadboard, a resistor, and some wires. Different letters/numbers can be represented by connecting different pins on the display to the battery, which turns on the LEDs in parallel. Seven segment displays are commonly used in many electrical applications, including alarm clocks, timers, and scales. In this tutorial, you will learn how to use your own 7-segment displays!Ī 7-segment display is an electronic device that can be used for displaying numerals and some letters. ![]()
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