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​24 VR = 2.2 kΩD​I = ?

A 24 V DC source drives current through a 2.2 kΩ resistor in series with a forward-biased silicon diode. Use the constant-drop model with 0.7 V per conducting diode. Find the current I in mA.

Vs = 24 VR = 2.2 kΩVD = 0.7 V
I = mA
2.Easy
+−Vs​5 VR = 470 ΩD​I = ?

A 5 V DC source drives current through a 470 Ω resistor in series with a forward-biased silicon diode. Use the constant-drop model with 0.7 V per conducting diode. Find the current I in mA.

Vs = 5 VR = 470 ΩVD = 0.7 V
I = mA
3.Medium
RC​ = 2.2 kΩβ = 50IC​ = ?VCC​ = 15 VRB​ = 820 kΩ

An NPN transistor with β = 50 is biased by a base resistor RB = 820 kΩ from the supply VCC = 15 V. The collector resistor is RC = 2.2 kΩ and the emitter is grounded. Take VBE = 0.7 V and assume the transistor is in the active region. Find the collector current IC in mA.

VCC = 15 VRB = 820 kΩRC = 2.2 kΩβ = 50VBE = 0.7 V
IC = mA
4.Medium
RC​ = 2.2 kΩβ = 100IC​ = ?RE​ = 680 ΩVCC​ = 12 VR1​ = 100 kΩR2​ = 22 kΩ

An NPN transistor with β = 100 has voltage-divider bias from VCC = 12 V: R₁ = 100 kΩ from VCC to the base and R₂ = 22 kΩ from the base to ground. The collector resistor is RC = 2.2 kΩ and the emitter resistor is RE = 680 Ω. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector current IC in mA.

VCC = 12 VR1 = 100 kΩR2 = 22 kΩRC = 2.2 kΩRE = 680 Ωβ = 100
IC = mA
5.Hard
+−≤ 19 V100 Ω6.2 V

A 6.2 V Zener regulator has a 100 Ω series resistor. The input can rise to 19 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.

Vin,max = 19 VVZ = 6.2 VR = 100 Ω
PZ,max = mW
6.Hard
RC​ = 330 Ωβ = 80IC​ = ?VCC​ = 5 V3.3 VRB​ = 100 kΩ

An NPN transistor with β = 80 switches a 330 Ω load resistor connected between VCC = 5 V and its collector. The emitter is grounded. The base is driven from a 3.3 V logic output through a base resistor RB = 100 kΩ. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the collector current IC in mA when the input is high. Decide first whether the transistor is saturated.

VCC = 5 VRC = 330 Ωβ = 80Vin = 3.3 VVBE = 0.7 VVCE(sat) = 0.2 VRB = 100 kΩ
IC = mA

Answer key

  1. 1. I = 10.59 mA
  2. 2. I = 9.149 mA
  3. 3. IC = 0.872 mA
  4. 4. IC = 1.688 mA
  5. 5. PZ,max = 793.6 mW
  6. 6. IC = 2.08 mA

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