COMPLETE POWER ELECTRONICS AND ALTERNATIVE ENERGY COURSE QUESTIONS WITH MULTISIM

Problems

Switch Characteristics

6-1

Locate a data sheet for a 1N4004 diode. Determine its average forward current, maximum forward voltage, and peak reverse voltage. Calculate the maximum power it must dissipate.

6-4

Design a switch using a Darlington pair to drive a 35 Ω load powered from a 24 V_dc supply. Determine the collector current, base current, base resistor, power delivered to the load, and the transistor power dissipation for a 75% duty cycle pulse.

6-6

Find a bipolar junction transistor with a maximum collector current of at least 9 A. From its data sheet determine the maximum collector-emitter voltage, worst case β (or h_FE), worst case V_CE, worst case V_BE, and worst case switching time.

6-8

Design a switch using an IRF630 to drive a 25 Ω load powered from a 150 V_dc supply. Determine the drain current, required gate pulse amplitude, power delivered to the load, and the transistor power dissipation for a 80% duty cycle pulse, and the required heat sink maximum thermal resistance for T_A = 60°C.

6-9

Locate a data sheet for an IRF630 MOSFET. Determine its maximum continuous drain current, maximum drain-to-source voltage, maximum gate-to-source voltage, junction-to-case thermal resistance, channel resistance at 100°C, gate-to-source voltage to drive it on, switching time, and gate capacitance.

6-10

Locate a data sheet for an IRFZ14 MOSFET. Determine its maximum continuous drain current, maximum drain-to-source voltage, maximum gate-to-source voltage, junction-to-case thermal resistance, channel resistance at 100°C, gate-to-source voltage to drive it on, switching time, and gate capacitance.

6-11

It is decided to use four IRF530s in parallel to drive a 35 Ω load from a 24 V_dc supply with a 75% duty cycle. Calculate the voltage drop across the paralleled transistors, and the power each transistor must dissipate. Is a heat sink needed? Prove your answer with a calculation.

6-18

In the circuit of Figure 6-31, transistors Q1 and Q4 are on and current flows as indicated. The load has a significant inductance. Explain, in detail how, and which Schottky diodes prevent the flyback when Q1 and Q4 are turned off.

Figure 6-31 ATTACHED

Problems

Thyristor Device Characteristics

Locate a full set of specifications for the Teccor S4006LS SCR and the Teccor Q4006LH triac. Use them to answer the following questions.

8-1

What is required to turn the Teccor S4006LS SCR on?

8-7

A 200 W light bulb is powered from a 120 V_rms line voltage, and is switched on and off with a S4006LS SCR.