Circuit Analysis - Transistor Tutorial - Common Emitter Circuit- Part 3

http://www.FreedomUniversity.TV. A series of videos on circuit analysis with applications to transistors. Transistors are important to know since these elements are a prelude to understanding how operational amplifiers work. Another example of the common emitter transistor configuration is discussed. For questions on these and other videos, contact Professor Santiago at john@e-liteworks.com or visit the above website.

Category:

Education

Tags:

• common emitter circuit
• transistors
• operational amplifiers
• how transistors work
• circuit analysis
• kirchoffs voltage law
• kirchoffs current law
• ohms law
• kcl
• kvl

[drjcircuits]

It should be 50 Not 50K. 50 is for beta. I'll annotate it on the video.

Dr J

[rave02able]

Vs={ [(4.545m)(20k)] /50 } +0.7

[rodcabzmd]

The reason why the answer for Vs is still correct though using 50k for beta is because Ic became 4.545A instead of 4.545mA. Its a Rule in division.

[shjh69fgx]

thank you man

[dreamer284]

@drjcircuits : Shouldn't the denominator be Rc * beta which is 2.2k * 50?

[barnamah]

at 3:53 vs<0.7 + (4.545*20k/50k) you used 50k ohms. Where does that come from? we have 50 (beta). If you ment the voltage across RB then it should have been

vs<0.7 + 4.545*20k

please clarify.

thank you

[UnderseaCaveman]

Thanks for great tutorial (I was able to follow that you mispoke and meant "50" for beta). To make more realistic, should add that Vce can not reach 0VDC (I looked up a 2n3904, and value is like 0.2VDC)....also Beta is dependent on Ic, which makes things a little trickier. I am studying the Common Emitter, and your tutorial was invaluble study... Mahalo, UC

[jharz20]

It's not 4.595mA, it's 4.545mA...

2.518V is correct...

[tainguyen01]

I'm sorry but to be too technical but i believe when you do the calculation for Vs the 4.595 value should be 4.595mA. Also, the answer should be 2.538V for Vs and not 2.518V. Anyways, thank you very much for the video good jobs.

[drjctu]

The 50 kohm at around 4:20 is when I mispoke and is not kohm but just 50. The 50 came from beta in the previous expression. Sorry for the confusion. Dr J