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July 1961 Popular Electronics[Table of Contents]
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Popular Electronics was published from October 1954 through April 1985. All copyrights are hereby acknowledged. See all articles from Popular Electronics.
Test your diode switch analysis skills here with six circuits designed by Mr. Robert P. Balin in the July 1961 issue of Popular Electronics. When evaluating the equivalent circuits with the diodes biased on or off, don't make the job more difficult for yourself by considering whether there is enough voltage or current to turn a particular diode on or not, just whether the diode is forward or reverse biased. Doing so reduces everything to simple series and parallel combinations. Redrawing each circuit either with a short for a forward biased diode and an open for a reverse biased diode makes the task easier.
By Robert P. Balin
Keeping in mind that a diode can pass current in one direction only, see if you can find the effective resistance across the battery in the circuits below. Assume that every resistor measures six ohms, and that the diodes have zero resistance in the forward direction, infinite resistance in the reverse direction.
|Here are other Popular Electronics quizzes:|
- Lamp Brightness Quiz, January
Diode Quiz Answers
1. 2 ohms
2. 6 ohms
3. 3 ohms
4. 9 ohms
5. 6 ohms
6. 2 ohms
Posted April 13, 2014