Pull Up and Pull Down Resistors

This video demonstrates the purpose of pull up and pull down resistors.

Category:

Education

Tags:

• Pull
• Up
• Down
• Resistors
• Circuit
• LED
• Green
• Red
• NPN
• Transistor
• Voltage
• Regulator
• Reed
• Switch
• Breadboard
• Ohm
• Power
• 1600
• MaH
• Schematic
• Diode
• Ground
• In
• Out
• Series
• Parallal
• Diagram
• Description
• Uses
• How
• To
• Purpose
• Inverter
• Not
• Gate
• Button
• Magnet
• Neodymium
• AustinOO3
• Austin

[AustinOO3]

Thanks and you're right about the current. If the current is too high, the LED will break and it is the same case with voltage (I think too much power is what breaks an LED). A resistor should be chosen, using ohms law, so around 20mA is through it. Since the resistor is in series with the LED, the current will also be 20mA through the LED.

I taught myself most of this, so I'm no expert either.

[exscape]

@bobesfanchi To call this reply late is a bit of an understatement, but in case someone else is wondering (I was): the green LED is powered in series with the 300 ohm pullup resistor, so that resistor takes care of the current limiting. The red LED would be powered directly off 5 volts if not for the limiting resistor added on the ground wire.

[stormbytes]

Thanks for the video. I spent the better part of 2 days reproducing your circuit on a breadboard to try and grasp what's happening. I get the pull down resistor part, but what's the pull-up pulling up exactly? best I was able to figure out was the pos-terminal on the LED ?

[jvcrules]

very clear explanation, thank you

[bobesfanchi]

Is there a reason you didn't put a protection resistor for the green LED?

[MattAnonymous]

@0:45 you mention that the 300Ohm resistor is there to limit voltage across the led. You mean 'current across the led', right? I have trouble conceptualizing sometimes so I could be wrong. Either way, excellent demo and explanation!

[httpyout]

thank u for showin me how to make an inverter men!!