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
+−20 V330 Ω3.3 VIR​ = ?

A 3.3 V Zener diode is fed from 20 V through a 330 Ω resistor, with no load connected. Find the current IR in the resistor.

Vin = 20 VVZ = 3.3 VR = 330 Ω
IR = mA
2.Easy
+−15 V150 Ω5.6 VIR​ = ?

A 5.6 V Zener diode is fed from 15 V through a 150 Ω resistor, with no load connected. Find the current IR in the resistor.

Vin = 15 VVZ = 5.6 VR = 150 Ω
IR = mA
3.Medium
RC​ = 1.5 kΩβ = 75VCC​ = 10 VRB​ = 390 kΩ

An NPN transistor with β = 75 is biased by a base resistor RB = 390 kΩ from the supply VCC = 10 V. The collector resistor is RC = 1.5 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 = 390 kΩRC = 1.5 kΩβ = 75VBE = 0.7 V
VCE = V
4.Medium
+−9 V220 Ω5.1 V680 ΩIZ​ = ?

A 5.1 V Zener regulator is fed from 9 V through 220 Ω and supplies a 680 Ω load. Find the Zener current IZ.

Vin = 9 VVZ = 5.1 VR = 220 ΩRL = 680 Ω
IZ = mA
5.Hard
RC​ = 150 Ωβ = 200VCC​ = 9 V5 VRB​ = ?

An NPN transistor with β = 200 switches a 150 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. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the largest base resistor RB, in kΩ, that still drives the transistor just into saturation.

VCC = 9 VRC = 150 Ωβ = 200Vin = 5 VVBE = 0.7 VVCE(sat) = 0.2 V
RB = kΩ
6.Hard
+−≤ 22 V330 Ω3.3 V

A 3.3 V Zener regulator has a 330 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 = 330 Ω
PZ,max = mW

Answer key

  1. 1. IR = 50.61 mA
  2. 2. IR = 62.67 mA
  3. 3. VCE = 7.317 V
  4. 4. IZ = 10.23 mA
  5. 5. RB = 14.66 kΩ
  6. 6. PZ,max = 187 mW

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