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WHAT'S YOUR ENGINEERING QUOTIENT?

Problem 3—Assume that each segment current limiting resistor is 300 ohms, anode drive is 5 V, the drop across each segment is 1.6 volts, and S1 is set to short the emitter of Q1 to ground, what is the maximum collector current that Q1 must handle?

ANSWER

Problem 4—Assuming R1 to be 4.7k, and a maximum collector current of 75mA, is what is the minimum current transfer ratio (beta) required of Q1?