Glossary a To F > 커뮤니티 카카오소프트 홈페이지 방문을 환영합니다.

They are often necessary when an antenna drives multiple TVs or when the antenna cable is longer than 150 feet. There is one key difference inductors oppose changes in current for a longer time when the current is higher; whereas a capacitor has a more pronounced effect when the current that charges or discharges it is lower; were we to eliminate the upstream resistance, the capacitor would charge instantaneously. A more accessible, but somewhat less accurate book, "Practical Electronics for Inventors" by Scherz, is probably also a good pick. Digital electronics are a class of easy to understand circuits that use discrete voltage ranges and square waveforms to transmit and process data - most commonly, representing binary numbers for use in Boolean algebra: a signal close to 0V is meant to signify "0", and a signal close to Vcc signifies "1". If you want to learn more about electronics, you should probably consider "The Art of Electronics" by Horowitz and Hill. These devices are more difficult to operate than lightbulbs, because they are very sensitive to the applied voltage - it must be enough to overcome the junction bias, but will result in a destructive current if off by as little as 0.2V. This is because diodes are only weakly conductive up until the potential of the junction is overcome - and shortly past that point, begin conducting like crazy.

Equipped with this knowledge, we can calculate that at this exact point, its internal resistance is 95 Ω. To build this circuit in practice, we can safely use use the nearest "preferred" resistor value, 330 Ω (which would actually allow 21.5 mA to flow through the device - well within the safety limits of most components). If the resulting flow of charges is slow enough, they will simply drain through the resistor; but if the rate of change is very high, the resistor will limit the current, and develop a substantial, what are electric cables momentary voltage difference across its terminals. The difference is that the smaller the resistor, and the larger the capacitor, the lower output impedance the filter will have - but the more power it will keep wasting, and the lower the impedance of the driving signal source would need to be to avoid distortion. In both these cases, a more sophisticated, active circuit - implementing a "real" current source - is necessary instead.

Fuses are meant to protect more expensive or harder-to-service components from being affected when something goes wrong (e.g., a stray metal item shorts traces on the circuit board); and to prevent the circuit from overheating and starting a fire if the problem goes uncorrected. The behavior of a high-pass filter fed with a square wave is perhaps even more interesting - with a voltage proportional to the rate of change of the input signal (hence the nickname: differentiator). Finally, with only B input in high state, Q1 will prevent Q2 from doing anything useful, but Q4 will conduct - again, resulting in "1". When the input voltage is close to 0V, the bottom transistor will not conduct, but the upper one will. The subsequent -2X swing will bring the output voltage close to 0V, then back to 2X, and so on. The interesting property of a diode (or any other p-n junction) is that while in this mode, the device will always maintain a potential close to that threshold voltage across its terminals: this electric field is necessary to keep the junction conductive, and the diode will develop an apparent resistance needed to maintain it.

An unexpected low-pass filter distortion seen in a digital signal is usually indicative of excessive capacitance of the signal path, perhaps because the connection is too long, or runs too close to others; while a high-pass pattern may indicate a broken trace or cut wire, forming an unwelcome capacitor in series with the source of the signal. In many cases, this is not a big deal; but when driving power-hungry devices, R1 and R2 may have to be so low, that the resulting quiescent current through them would render the arrangement completely impractical. There is some minimal gate voltage needed to cause a sufficient charge separation; this threshold voltage - VGS(TH) - depends on the geometry of the transistor, and generally ranges from 1 to 2V (but may be as high as 3-4V for high power devices). When adjacent channel stations broadcast from the same tower or adjacent towers they must have an agreement that neither will exceed 10 times the other’s power.