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How emitter bypass resistor stabilizes the amplifier against temperature?
Wiki User
∙ 12y ago
In the common emitter (Class A) amplifier design of a BJT, gain is collector resistance divided by emitter resistance, or hFe, whichever is less. If the emitter resistance is zero, then gain is hFe. In this configuration, gain is unstable, because hFe is temperature dependent. In fact, under certain circumstances, a BJT can experience thermal runaway. The emitter resistor (along with the collector resistor) places a limit on the expected gain of the stage. If, for example, you design with a ratio of 10, then you expect a gain of 10. If hFe is 25-100, gain is still 10.
Wiki User
∙ 12y ago
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How are current ratings given to a resistor?
Resistors are not usually given 'current ratings' but, rather, 'power ratings' expressed in submultiples of the watt. It is then up to the user to calculate the safe maximum operating current for a particular resistor, by manipulating the equation: P = I2 R.Since a power rating is dependent upon the resistor's ability to dissipate energy by heat transfer, the actual power rating is dependent upon the surface area and, hence, the physical size of the resistor. So you will find that resistors come in a variety of physical sizes for any given resistance value.Unfortunately, power ratings are not indicated through colour codes, etc., so you will have to either specify its power rating when you purchase a resistor, or match your existing resistor against a scale-drawing to determine its power rating.
How capillary thermostat works?
The capillary thermostat has a capillary tube which is usually filled with a refrigerant which usually contracts or expands due to temperature. As the temperature expands this liquid and in turn this pressure presses against a bellows that pushes against a switch , the switch closes and the refrigerator runs until the capillary cools enough to decrease the pressure and the opposite happens.
What does a 100k resistor do?
Resistance: Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law: Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms) where: Voltage [V]= the energy lost across an component (voltage measured in volts). Current [I] = the charge (electrons) flowing through an component (current measured in Amps). Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady. When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life. Resistor: The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by: P = V x I (Power = Voltage x Current) (power measured in watts) There are also many types of resistors including: · Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo). · Thermistor - changes resistance when the temperature changes (used in a thermostat). · Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights). Resistor Example: An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current. But which value of resistance should the have resistor? Uses ohms law: R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms (Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED) But which value of power should the resistor be capable of handling? P = V x I = (12.0 - 2.0) / 0.02 = 0.2 WattsNote: k = x1,000 M = x1,000,000 G = x1,000,000,000So a 10k resistor = 10kohms = 10,000ohms
What is the functions of a resistor?
Resistance:Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law:Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms)where:Voltage [V]= the energy lost across an component (voltage measured in volts).Current [I] = the charge (electrons) flowing through an component (current measured in Amps).Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady.When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life.Resistor:The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by:P = V x I (Power = Voltage x Current) (power measured in watts)There are also many types of resistors including:· Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo).· Thermistor - changes resistance when the temperature changes (used in a thermostat).· Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights).Resistor Example:An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current.But which value of resistance should the have resistor? Uses ohms law:R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms(Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED)But which value of power should the resistor be capable of handling?P = V x I = (12.0 - 2.0) / 0.02 = 0.2 Wattshope this helpsofiu9njkgugi The main function of resistor is to control the electric current passing through the system. In automobile it is used in many areas like Body Areas & Cabin Controls, Integrated Drive Train & Starter/Alternators (including 42V systems), DC/DC Converters, Lighting Supplies, Engine Management & Ignition/Injection System and Hybrid/Electric Vehicle.
Where is resistor used?
The resistors are mainly used to reduce the current
What is a fusible resistor?
A resistor designed to protect a circuit against overload.
Where is the ballast resistor located on a 1989 350 Dodge Van?
Usually against the firewall in the center It most liley does not have a ballast resistor.
In the circuit I accidentally connected output of the amplifier to the ground. Will it damage my chips if all chips are powered from 3V and -3V batteries?
It depends on the output impedance of the circuit, and on the value that the amplifier was attempting to produce. If the amplifier was idle, and properly nulled, then the expected output would be zero, so grounding it might not hurt. If it was attempting to produce an output, then you need to look at the possible current produced vs the maximum rated current of the chip. This is where the output impedance comes in. Usually, there is a resistor there to protect against just this sort of thing. Back to the idle state, however. If you ground the output, you remove the feedback loop and destabilize the amplifier. In all probability, then, it attempted to pull to one or the other rail. Again, this is what that resistor is for. The final answer, in all probability, then, is yes, you damaged the chips, unless the chips themselves were internally current limited. Time to check the datasheet.
Where is the blower resistor on a 2005 Chevy Trailblazer?
Blower resistor is behind the blower motor up against the firewall you can see wires hanging down from it. (Mite be called blower control module in 2005 models.)
Where is the ballast resistor located on a 1985 Dodge V8 Prospector van?
Usually against the firewall in the center section
Do you have to take the blower motor off first before you can get to the blower motor resistor on a 2000 Pontiac Grand Prix?
No you dont but is a tight fit. The resistor is way back against the fire wall. It is sloted so i believe you do not have to remove the bolts completely because one is really hard to get. No you dont but is a tight fit. The resistor is way back against the fire wall. It is sloted so i believe you do not have to remove the bolts completely because one is really hard to get.
The skin acts as a barrier against germs and also controls body temperature?
True. The skin acts as a barrier against germs and also controls body temperature.
Exactly where is heater blower resistor on a 1999 Alero?
The blower resistor is ahead of the blower motor under the pass. side of the dash. It is butt up against the firewall and held in by 2-3 bolts. 5.5 mm heads. Very difficult to get to. Will need a special swivel socket to get ot the bolts.found out this is a resistor pack under the glove box -sunil Maryland
What is the purpose of a mercury thermometer?
to see what is the temperature The Mercury expands or contracts depending on the temperature so its height against the scale on the thermometer tells you the temperature.
What is the purpose of Mercury in a Thermometer?
to see what is the temperature The mercury expands or contracts depending on the temperature so its height against the scale on the thermometer tells you the temperature.
Where is the blower motor resistor for a 99 Olds Intrigue?
Hi, I just replaced the resistor on my '98 Intrigue- it's quite possible they are located similarly. The resistor is located under the dash on the passenger side, right behind the blower. I had to pull the blower out to gain better access to the resistor assembly. There is a short cable assembly that connects the resistor to the blower so if you look for the two wires that come out of the back of the blower they should lead you right to the resistor. The resistor is very hard to get to because of the hex head screws being right up against the floorboard but you only need to loosen the two back screws and remove the one in front to be able to pull the resistor assembly out. If you can get a small 5/16" socket on the screw heads you should be able to loosen them enough. There will be a larger cable assembly plugged into the resistor also. The whole procedure took me about a half hour, not a bad job but just hard to maneuver down there. !
Where is the blower motor resistor on a 2000 Pontiac grand prix se?
the blower moter resistor is located on the passenger side. remove kick panel under dash and it is staight up against the firewall. three 5.5mm bolts hold it in,it is very tight in there.gm Jim
