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.

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1.Easy
+−Vs​24 VR = 4.7 kΩD​I = ?

A 24 V DC source drives current through a 4.7 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 = 4.7 kΩVD = 0.7 V
I = mA
2.Easy
+−24 V150 Ω5.6 VIR​ = ?

A 5.6 V Zener diode is fed from 24 V through a 150 Ω resistor, with no load connected. Find the current IR in the resistor.

Vin = 24 VVZ = 5.6 VR = 150 Ω
IR = mA
3.Medium
RC​ = 1.2 kΩβ = 150VCC​ = 10 VRB​ = 330 kΩ

An NPN transistor with β = 150 is biased by a base resistor RB = 330 kΩ from the supply VCC = 10 V. The collector resistor is RC = 1.2 kΩ and the emitter is grounded. Take VBE = 0.7 V and assume the transistor is in the active region. Find the collector–emitter voltage VCE.

VCC = 10 VRB = 330 kΩRC = 1.2 kΩβ = 150VBE = 0.7 V
VCE = V
4.Medium
RC​ = 1 kΩβ = 100RE​ = 470 ΩVCC​ = 12 VR1​ = 22 kΩR2​ = 12 kΩ

An NPN transistor with β = 100 has voltage-divider bias from VCC = 12 V: R₁ = 22 kΩ from VCC to the base and R₂ = 12 kΩ from the base to ground. The collector resistor is RC = 1 kΩ and the emitter resistor is RE = 470 Ω. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector–emitter voltage VCE.

VCC = 12 VR1 = 22 kΩR2 = 12 kΩRC = 1 kΩRE = 470 Ωβ = 100
VCE = V
5.Hard
+−≤ 22 V100 Ω3.3 V

A 3.3 V Zener regulator has a 100 Ω series resistor. The input can rise to 22 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.

Vin,max = 22 VVZ = 3.3 VR = 100 Ω
PZ,max = mW
6.Hard
+−≤ 26 V680 Ω5.6 V

A 5.6 V Zener regulator has a 680 Ω series resistor. The input can rise to 26 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.

Vin,max = 26 VVZ = 5.6 VR = 680 Ω
PZ,max = mW

Answer key

  1. 1. I = 4.957 mA
  2. 2. IR = 122.7 mA
  3. 3. VCE = 4.927 V
  4. 4. VCE = 2.561 V
  5. 5. PZ,max = 617.1 mW
  6. 6. PZ,max = 168 mW

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