Another problem, voltage characteristic in a diode circuit

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SUMMARY

The discussion revolves around calculating the base current (I_B) in a bipolar junction transistor (BJT) circuit using Kirchhoff's Voltage Law (KVL). The user attempts to apply Ohm's Law and KVL to find I_B, estimating values for the input voltage (V_i) and the base-emitter voltage drop (V_B). The calculated base current is approximately 93.75 microamperes, based on the assumption of V_B being 0.65V and V_i being 1V. The conversation highlights the importance of understanding BJT characteristics and proper application of circuit laws.

PREREQUISITES
  • Bipolar Junction Transistor (BJT) fundamentals
  • Kirchhoff's Voltage Law (KVL)
  • Ohm's Law application in circuits
  • Understanding of diode voltage drops
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  • Explore diode characteristics and their impact on circuit analysis
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Electronics students, circuit designers, and anyone involved in analyzing or designing BJT circuits will benefit from this discussion.

amitjakob
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Good morning lovely people !

As I got some really helpful advice here yesterday i though i'd try it again, hopefully you haven't yet had too much from me (-:

So my question is concerning the attached PDF file (Last problem #3)

i am asked to find the current I_B in 3a) and 3c) but to my very low understanding wouldn't it simply be Vi/Ri (Ohms Law) ??

Thanks for the patience :smile:
 

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try kvl. looks like its a bjt (just zoomed in). factor in diode drop, Vi, etc etc
 
Thanx but ...

do you mind explaining a little bit more, I'm kinda newbie (-:
whats a bjt ?
thanks for the patience:cool:
 
edmondng said:
try kvl. looks like its a bjt (just zoomed in). factor in diode drop, Vi, etc etc

Tried KVL on the most left handside mesh.
Im not sure its right though ...

i guessed V_Ri + V_B = V_i then substitute V_B=0.65V (pretty sure its a bad guess) and V_i=1V (Which is given)

Yeilds I_Ri=I_B= 93.75 microA ? makes sense ?
 

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