Mr Carlson's Lab
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Lesson 2 Part 2 - How To Fix Just About Anything Electronic!
🕑 Added 2023-01-03 03:10:31 +0000 UTCIn this video we look at how an NPN and PNP transistor work together to create a "Rail Switch." These switches are in many pieces of equipment, studying the schematic and topology of this circuit will make the recognition of this circuit come naturally. We build this circuit together on a breadboard and look at how it functions to control a load. See how the transistors act as switches that control each other. See how to bypass one complete stage to enhance your troubleshooting skills. The circuit in this video only requires a power supply (or battery pack,) and a DMM to troubleshoot and analyze. Lots of great information to benefit you here!
NOTE: If you're using the information in this video or attachments, building the circuits, and using your own test equipment, or any equipment, you are doing so at your own risk. If you do not understand this, or do not agree with this, Do Not use this information, IE: (The information in the video, and in any attachments provided,) and do not build anything.
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Comments
Carleton Wheeler
I don't understand why the voltage at the npn collecter is 4.39 volts with no input. that point is across a resistor and and isnt there a voltage drop accross a resistor? is it b/c there very little current (voltage drop is IR)? if so it seems odd that the potential can be extended accross the resistor, as soon as that potential is tapped/utilized, current will flow and the potential will drop across the resistor. (?)
Peer Verbeek
Could you explain the electronic pull with the transistors a little bit more? So we can visualize what happens at the E, B, C transistor points. I have a hard time understanding what happens to the next transistor when something is pulled low or pushed high trough a resistor to the next transistor. The emitter or base does something via a resistor path to the next transistor. The simple rules would be nice. Could you visualize it as..... up and up goes down this voltage, does up and thus that down to that voltage.
