By Sam Wilson
The questions this month are taken from the July 1986 and August 1986 issues of ES&T. Are you keeping up with the technology?
1. By separating the camera head (lens and charge-coupled device image sensor) from the rest of the camera's electronics, engineers have developed a video camera device that's roughly the size of a human:
A.) neck.
B.) wrist.
C.) thumb.
2. As a transistor parameter, gamma would normally be used in the design of
A.) oscillator circuits.
B.) common emitter audio amplifiers.
C.) follower circuits.
D.) RF amplifiers.
3. The rubberlike plastic interface material that is used to connect components to a printed circuit board without soldering is called
4. Which of the following is a likely result of 19kHz pilot leakage in an FM stereo receiver?
A.) Overload AGC B.) Poor low frequency response C.) Loss of afc D.) Speaker overload
5. Referring to the receiver in an audio system, the manufacturer may give a usable sensitivity rating of 1.5µV or 2µV. Which of the following is true?
A.) The higher the number, the better the receiver.
B.) The lower the number, the better the receiver.
6. Referring, again, to the receiver in an audio system, a db quieting is preferred over usable sensitivity because it
A. is the usable signal rating.
B. is the signal at which the receiver can maintain automatic frequency control.
7. Far cleaning the upper cylinder unit in a VCR, ...
A.) use an emery board.
B.) use head cleaning sticks.
C.) soap and water is best.
8. Most microcomputers are
A.) CMOS. B.) TTL. C.) ECL. D.) RTL.
9. For a quick check of an audio amplifier for frequency response, ...
A.) a sawtooth waveform can be used instead of a square wave.
B.) a sawtooth waveform cannot be used instead of a square wave.
10.) A TVRO antenna mount that allows the user to receive signals from all satellites in the geosynchronous, or Clarke, orbit simply by turning the dish on its axis is called ...
A.) alt-azimuth mount.
B.) polar mount.
Answers to the Quiz
1. C. The video camera device was announced by Toshiba. It is described on page 12 of the July 1986 issue.
2. C. "What Do You Know About Electronics?" by Sam Wilson (page 52).
Although many readers wrote to explain gamma, and the use of gamma in designing follower circuits, they have not convinced me that gamma is an important parameter. Of course, this is a matter of opinion. Some of the letters I received disagree with that opinion.
3. A conductive elastomer. This material serves two purposes. It holds the component in place and it completes the electrical connection.
4. D. The 19kHz pilot signal is within the frequency range of tweeter speaker response. The signal may be overloading the speaker, but the customer may not be able to hear the offending frequency. Refer to page 64 of the July 1986 issue, "Audio Corner," by Kirk Vistain.
5. B. The lower the number, the better the receiver is able to reproduce weak signals. However, the rating is misleading because the reproduced sound may have excessive noise when the receiver is working with very low amplitude signals. A better rating is decibel quieting. Refer to page 64 of the July 1986 issue, "Audio Corner," by Kirk Vistain.
6. A. The decibel quieting of an FM receiver tells the amount of rms signal strength (in microvolts) that is needed to produce a given amount of noise reduction. The noise in a receiver is greatly reduced when a strong signal is received. The reason is that the signal activates the AGC circuitry and reduces the gain in the RF stages. Refer to page 64 of the July 1986 issue, "Audio Corner," by Kirk Vistain.
7. B. Manufacturers of VCR equipment and the Electronic Industries Association/Consumer Products Group both recommend the use of head cleaning sticks.
The sticks use ultra-cleaned natural chamois leather for the cleaning material. Refer to page 28 of the August 1986 issue. The article is titled "Maintenance and Lubrication," by Conrad Persson.
8. A. In the continuing series titled "Audio Corner," Kirk Vistain recommends taking care to prevent static damage to the CMOS microcomputers. They, like all CMOS components, are susceptible to damage by static discharge.
9. A. Although the square wave test is more popular, the sawtooth wave test could be equally useful.
In fact, the sawtooth test will show if clipping occurs, but the square wave test is not good for that purpose. Refer to page 58 of the August 1986 issue in an article titled "What Do You Know About Electronics?" by Sam Wilson.
10. A polar mount is so designed and constructed that it permits the antenna, when it is turned on a polar axis, to sweep or track the geosynchronous orbit. Refer to page 43 of the August 1986 issue, "Satellite Receiving Antennas," by Jim Kluge.
What do you know about electronics?--Microprocessor tuning