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Slope of the volts vs resistance characteristics for fluroscent and incandescent lamps?
the resistance of an incandescent lamp is very low until it reaches its operating temperature of 6000deg K or so
get a sixty watt bulb and measure its resistance chances are its under 5 ohms
depending on the mass of tungsten it takes a few cycles at this 60 amps to get up to temperature.
voltage is constant calling the wiring a voltage source (if the wiring didnt have resistance the bulbs of higher wattages would probably burn out when starting)
fluorescent lamps have a bit of Mercury in a near vacuum nearly infinite resistance when cold
it is heated to boiling with a combination of either filaments and/or high voltage
then the gas changes to plasma and its in essence a better conductor than solid metal at that temperature 9000K or so
an 8foot tube starts at 800v to 1000v and may run at under 100
depending on the ballast (preheat. rapid start. instant start)
and the power (normal,HO,VHO,SHO)
the ballast mostly limits the current the plasma can consume but is necessary to start the plasma conducting in longer tubes
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What does the slope of voltage-current curve represent?
It depends. If voltage is drawn along the horizontal axis, then the slope at any point on the graph represents the reciprocal of resistance at that point. If current is drawn along the horizontal axis, then the slope at any point on the graph represents the resistance at that point.
What is the incremental resistance obtained from the diode equation?
The incremental resistance of a diode is the inverse of the slope of the V-I curve at the operating point.
What are Ac load lines in an amplifier and how they are drawn?
The dc load resistance is Rc but the AC Load resistance is (RcRl). If a load line is drawn the slope of which is -1(Rc Rl) . Then it is called an AC load line and it is to be used when the transistor is operating as an amplifier.
Why does slope overload occur in delta modulation?
To reduce slope overload distortion ,the step size must be increased when the slope of the input signal is high. The sawtooth is better able to match the message in the regions of steep slope.
What is dynamic resistance of diode?
The Current-Voltage relationship of a diode is not constant (not a straight line) and hence the resistance cannot be measured. Due to this non-linear nature of the the curve, there exists a unique value of resistance at every point of the curve which is called dynamic resistance (not static of constant resistance). The dynamic resistance equals the change in voltage divided by the change in current, when the voltage is changed by a small amount. In other words it is the slope of the graph of voltage against current. The dynamic resistance is different at different current values. About 30 years ago, and I do not remeber the brand or maker, there was a digital multimeter that DID measure dynamic resistance in diodes. It was a God Send for testing diodes in circuit. Diodes only conduct in one direction, so the device would show an open in one direction and a resistance under 1000 ohms on the other or a short (0 ohms).
