Diodes & transistors worksheet with answers

Free printable Diodes & transistors worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+−Vs​15 VR = 1.5 kΩD1​D2​I = ?

A 15 V DC source drives current through a 1.5 kΩ resistor in series with two forward-biased silicon diodes. Use the constant-drop model with 0.7 V per conducting diode. Find the current I in mA.

Vs = 15 VR = 1.5 kΩVD = 0.7 V
I = mA
2.Easy
+−Vs​6 VR1​ = 1 kΩR2​ = 3.3 kΩID​ = ?

A 6 V DC source is connected through resistor R₁ = 1 kΩ to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 3.3 kΩ, and a silicon diode with its anode at X. Use the constant-drop model with 0.7 V. Find the diode current ID in mA.

Vs = 6 VR1 = 1 kΩR2 = 3.3 kΩVD = 0.7 V
ID = mA
3.Medium
+−9 V220 Ω5.6 V3300 ΩIZ​ = ?

A 5.6 V Zener regulator is fed from 9 V through 220 Ω and supplies a 3300 Ω load. Find the Zener current IZ.

Vin = 9 VVZ = 5.6 VR = 220 ΩRL = 3300 Ω
IZ = mA
4.Medium
+−18 V100 Ω5.1 V2200 ΩIZ​ = ?

A 5.1 V Zener regulator is fed from 18 V through 100 Ω and supplies a 2200 Ω load. Find the Zener current IZ.

Vin = 18 VVZ = 5.1 VR = 100 ΩRL = 2200 Ω
IZ = mA
5.Hard
+−≤ 30 V270 Ω9.1 V

A 9.1 V Zener regulator has a 270 Ω series resistor. The input can rise to 30 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.

Vin,max = 30 VVZ = 9.1 VR = 270 Ω
PZ,max = mW
6.Hard
V (V)I (mA)0.6618.18Q = ?

A diode is modelled as 0.6 V in series with 20 Ω (it conducts above 0.6 V). It is in series with a 330 Ω resistor across a 6 V supply. Find the operating current ID where the diode line meets the load line.

Vs = 6 VR = 330 ΩV0 = 0.6 Vrd = 20 Ω
ID = mA

Answer key

  1. 1. I = 9.067 mA
  2. 2. ID = 5.088 mA
  3. 3. IZ = 13.76 mA
  4. 4. IZ = 126.7 mA
  5. 5. PZ,max = 704.4 mW
  6. 6. ID = 15.43 mA

Full step-by-step solutions: practise this topic on examproblems.com.