Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Post History

66%
+2 −0
Q&A Calculating base voltage of NPN transistor

For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknowns (current Ib2 neglected), Let me try: Vb1-Vx=I5*R5 I5=IC4+Vb1/R3 IC4=Ue...

posted 5mo ago by LvW‭  ·  edited 5mo ago by LvW‭

Answer
#3: Post edited by user avatar LvW‭ · 2024-05-12T14:23:24Z (5 months ago)
  • For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknowns (current Ib2 neglected),
  • Let me try:
  • * Vb1-Vx=I5*R5
  • * I5=IC4+Vb1/R3
  • * IC4=Ue4/R4
  • * Ue4=VB2-0.7
  • These 4 equations (simple insertion procedure) result in:
  • * Vb1-Vx=R5[(Vb2-0.7)/R4 + Vb1/R3]
  • * Now we can Vb2 express as a function Vx (voltage division) and we have an equation with the **two unknowns Vb1 and Vx**.
  • * A **second equation for Vb1 and Vx** can be derived from
  • (V1-Vx)/R10=I10=I5+(Vx/Rx) with I5=(Vb1-Vx)/R5.
  • * The resistor Rx is the total resistance between Vx and ground.
  • For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknowns (current Ib2 neglected),
  • Let me try:
  • * Vb1-Vx=I5*R5
  • * I5=IC4+Vb1/R3
  • * IC4=Ue4/R4
  • * Ue4=VB2-0.7
  • These 4 equations (simple insertion procedure) result in:
  • * Vb1-Vx=R5[(Vb2-0.7)/R4 + Vb1/R3]
  • * Now we can Vb2 express as a function Vx (voltage division) and we have an equation with the **two unknowns Vb1 and Vx**.
  • * A **second equation for Vb1 and Vx** can be derived from
  • (V1-Vx)/R10=I10=I5+(Vx/Rx) with I5=(Vb1-Vx)/R5.
  • * The resistor Rx is the total resistance between Vx and ground.
  • * Last step: Solve the system with two equations for two unknowns.
#2: Post edited by user avatar LvW‭ · 2024-05-12T14:21:48Z (5 months ago)
  • For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknown (Current Ib2 neglected),
  • Let me try:
  • * Vb1-Vx=I5*R5
  • * I5=IC4+Vb1/R3
  • * IC4=Ue4/R4
  • * Ue4=VB2-0.7
  • These 4 equations (simple insertion procedure) result in:
  • * Vb1-Vx=R5[(Vb2-0.7)/R4 + Vb1/R3]
  • * Now we can Vb2 express as a function Vx (voltage division) and we have an equation with the **two unknowns Vb1 and Vx**.
  • * A **second equation for Vb1 and Vx** can be derived from
  • (V1-Vx)/R10=I10=I5+(Vx/Rx) with I5=(Vb1-Vx)/R5.
  • * The resistor Rx is the total resistance between Vx and ground.
  • For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknowns (current Ib2 neglected),
  • Let me try:
  • * Vb1-Vx=I5*R5
  • * I5=IC4+Vb1/R3
  • * IC4=Ue4/R4
  • * Ue4=VB2-0.7
  • These 4 equations (simple insertion procedure) result in:
  • * Vb1-Vx=R5[(Vb2-0.7)/R4 + Vb1/R3]
  • * Now we can Vb2 express as a function Vx (voltage division) and we have an equation with the **two unknowns Vb1 and Vx**.
  • * A **second equation for Vb1 and Vx** can be derived from
  • (V1-Vx)/R10=I10=I5+(Vx/Rx) with I5=(Vb1-Vx)/R5.
  • * The resistor Rx is the total resistance between Vx and ground.
#1: Initial revision by user avatar LvW‭ · 2024-05-12T14:21:09Z (5 months ago)
For my opinion, it is not too complicated to reduce the various equations to a system of two equations with two unknown (Current Ib2 neglected),
Let me try:

* Vb1-Vx=I5*R5
* I5=IC4+Vb1/R3
* IC4=Ue4/R4
* Ue4=VB2-0.7

These 4 equations (simple insertion procedure) result in:

* Vb1-Vx=R5[(Vb2-0.7)/R4 + Vb1/R3]
* Now we can Vb2 express as a function Vx (voltage division) and we have an equation with the **two unknowns Vb1 and Vx**.

* A **second equation for Vb1 and Vx** can be derived from 
(V1-Vx)/R10=I10=I5+(Vx/Rx) with I5=(Vb1-Vx)/R5.
* The resistor Rx is the total resistance between Vx and ground.