How can I design a transistor switch for a 10-Ohm load with a +5V supply?

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SUMMARY

The discussion focuses on designing a transistor switch for a 10-Ohm load powered by a +5V supply, specifically using an NPN transistor with a beta of 50. To fully saturate the transistor, the collector-emitter voltage must be less than 0.3V. Participants emphasize the importance of calculating the collector current (Ic) accurately by incorporating the saturation voltage (Vce,sat) and determining the necessary base current (Ib) based on the defined beta value.

PREREQUISITES
  • Understanding of transistor operation, specifically NPN transistors
  • Familiarity with Ohm's Law and basic circuit analysis
  • Knowledge of transistor parameters, including beta and saturation voltage
  • Ability to perform calculations involving collector current and base current
NEXT STEPS
  • Calculate the collector current (Ic) for a 10-Ohm load at +5V using Vce,sat
  • Determine the base current (Ib) required for saturation using the transistor's beta
  • Explore circuit design techniques for transistor switches in low-voltage applications
  • Review practical examples of transistor switching circuits in electronics textbooks
USEFUL FOR

Electronics students, hobbyists designing low-power circuits, and anyone interested in understanding transistor switching applications.

YAHA
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Homework Statement



I am given a problem for my electronics class that asks to design a transistor switch that will switch a 10-Ohm load powered from a +5V supply. The transistor beta is about 50.

It also asks which current is needed to turn the transistor fully on (saturate it so that the collector-emitter voltage is less than 0.3V)

Homework Equations






The Attempt at a Solution



My biggest problem is that the book we use SUCKS. I am simply lacking material and, maybe, some examples. I have tried approaching the instructor, but his explanations do not "speak" to me.

I know what the circuit looks like. I then proceed to substitute the transistor with a diode+current source model. After that, I am befuddled.

Any help and preferably hints are appreciated!
 
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YAHA said:

Homework Statement



I am given a problem for my electronics class that asks to design a transistor switch that will switch a 10-Ohm load powered from a +5V supply. The transistor beta is about 50.

It also asks which current is needed to turn the transistor fully on (saturate it so that the collector-emitter voltage is less than 0.3V)

Homework Equations






The Attempt at a Solution



My biggest problem is that the book we use SUCKS. I am simply lacking material and, maybe, some examples. I have tried approaching the instructor, but his explanations do not "speak" to me.

I know what the circuit looks like. I then proceed to substitute the transistor with a diode+current source model. After that, I am befuddled.

Any help and preferably hints are appreciated!

Can you show us the circuit diagram that you would use? If you have about 5V across a 10 Ohm load, what will the collector current of the NPN transistor be?

Now get a more accurate number for Ic by including the Vce,sat number in the calculation of the collector current. What is it now?

How is Beta defined? Using the definition of Beta, what can you say about the base current required to support the Ic value that you calculated?
 
I am not really sure how I could show you. Your hints were helpful though :) I was able to "see" it. This has been a bizarre class. I can do QM and Solid State of diodes and transistors alright. However, when it comes to their applications, I am lost.
 

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