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
+−15 V330 Ω5.1 VIR​ = ?

A 5.1 V Zener diode is fed from 15 V through a 330 Ω resistor, with no load connected. Find the current IR in the resistor.

Vin = 15 VVZ = 5.1 VR = 330 Ω
IR = mA
2.Easy
+−15 V470 Ω3.3 VIR​ = ?

A 3.3 V Zener diode is fed from 15 V through a 470 Ω resistor, with no load connected. Find the current IR in the resistor.

Vin = 15 VVZ = 3.3 VR = 470 Ω
IR = mA
3.Medium
+−18 V270 Ω3.3 V1000 ΩIZ​ = ?

A 3.3 V Zener regulator is fed from 18 V through 270 Ω and supplies a 1000 Ω load. Find the Zener current IZ.

Vin = 18 VVZ = 3.3 VR = 270 ΩRL = 1000 Ω
IZ = mA
4.Medium
+−9 V270 Ω5.6 V1000 ΩIZ​ = ?

A 5.6 V Zener regulator is fed from 9 V through 270 Ω and supplies a 1000 Ω load. Find the Zener current IZ.

Vin = 9 VVZ = 5.6 VR = 270 ΩRL = 1000 Ω
IZ = mA
5.Hard
+−≤ 11 V270 Ω5.1 V

A 5.1 V Zener regulator has a 270 Ω series resistor. The input can rise to 11 V, and the load may be disconnected. Find the largest power PZ,max the Zener must dissipate.

Vin,max = 11 VVZ = 5.1 VR = 270 Ω
PZ,max = mW
6.Hard
RC​ = 100 Ωβ = 50IC​ = ?VCC​ = 9 V5 VRB​ = 1 kΩ

An NPN transistor with β = 50 switches a 100 Ω load resistor connected between VCC = 9 V and its collector. The emitter is grounded. The base is driven from a 5 V logic output through a base resistor RB = 1 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 = 9 VRC = 100 Ωβ = 50Vin = 5 VVBE = 0.7 VVCE(sat) = 0.2 VRB = 1 kΩ
IC = mA

Answer key

  1. 1. IR = 30 mA
  2. 2. IR = 24.89 mA
  3. 3. IZ = 51.14 mA
  4. 4. IZ = 6.993 mA
  5. 5. PZ,max = 111.4 mW
  6. 6. IC = 88 mA

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