### Transcription of Voltage and Current Division Rules - GUC

1 **Voltage** and **Current** **Division** **Rules** **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 1. Objectives To apply the **Voltage** and **Current** **Division** **Rules** . **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 2. **Voltage** **Division** For example, we know i = VTOTAL / (R1 + R2 + R3). so the **Voltage** over the first resistor is V1=i R1 = R1 VTOTAL / (R1 + R2 + R3). R1. v1 = V. R1 + R2 + R3. To find the **Voltage** over an individual resistance in series, take the total series **Voltage** and multiply by the individual resistance over the total resistance. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 3. Example determine the **Voltage** across each resistor **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 4.

2 Example determine the **Voltage** across each resistor vs is =. R1 + R2. iS. R1. v1 = vs R1 + R2. iS. R2. v2 = vs R1 + R2. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 5. Summary The source **Voltage** v is divided among the resistors in direct proportion to their resistances the larger the resistance, the larger the **Voltage** drop. This is called the principle of **Voltage** **Division** , In general If a **Voltage** divider has N resistors (R1,R2, .. , RN) in series with the source **Voltage** v, the nth resistor (Rn) will have a **Voltage** drop of **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 6. **Current** **Division** If we know the **Current** flowing into two parallel resistors, we can find out how the **Current** will divide up in one step.

3 V i1 =. R1. 1 R1 R 2 R2. i1 = i i1 = i R1 R1 + R2 R1 + R2. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 7. Note that this differs slightly from the **Voltage** **Division** formula for series resistors R2 = 0 implies that i1 = 0, i2 = i. R2 = , that is, R2 is an open R2 , then Req = R1. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 8. Example Find i1 and i2 in terms of is is = i1 + i2 is R1 R2. i1 i2. v1 = v2. i1 R1 = i2 R2. R1 R1 R2 + R1. i2 = i1 is = i1 + i1 = i1. R2 R2 R2. R2. i1 = is R1 + R2. R1. i2 = is R1 + R2. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 9. Example Use **Voltage** and **Current** **Division** **Rules** to find Vo and io 6 3.

4 =2. 6+3. Step 1. Step 1. Step 2. **hisham** El-Sherif ELCT708: Electronics for Biotechnology Electronics and Electrical Engineering Department 10.