Issue 264: EQ Answers

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The answers to the Circuit Cellar 264 (July) Engineering Quotient are now available. The problems and answers are listed below, along with a schematic. Problem 1a—Is it possible to transmit on-off (DC) signals between two pieces of equipment in both … Continue reading

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Issue 262: EQ Answers

Problem 1—The classic two-transistor astable multivibrator is shown below. Typically, R2 and R3 have at least 10 times the value of R1 and R4. This circuit oscillates, with Q1 and Q2 turning on alternately. From the point in time in … Continue reading

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Issue 260: EQ Answers

These are the answers to the EQ questions that appeared in Circuit Cellar 260 (March 2012). Problem 1—In an RS-232 interface, why is the idle or “mark” level a negative voltage? Answer 1—RS-232 was developed in the days when people were connecting … Continue reading

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Issue 258: EQ Answers

These are the answers to the EQ questions that appeared in Circuit Cellar 258(January 2012). Answer 1—Q1 and Q2 are wired as a differential amplifier, but in this digital application, it’s probably better to think of them as a current … Continue reading

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