Depending on context, it could be an infra-red emitter. An emitter that emits at a wavelength longer than that of visible red.
infra red emitter is a special pn juction device in which emitter region emits infrared rays
The emitter resistor in a common emitter configuration provides negative feedback to the transistor, reducing both its voltage gain and distortion.
Emitter
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
In physics, an alpha emitter is a radioactive substance which decays by emitting alpha particles.
The gain of a common-emitter amplifier is collector resistor divided by emitter resistor, or hFe, whichever is less. Since hFe depends on temperature, designing the amplifier to be dependent on resistance ratio makes it more stable. As such, the emitter resistance serves to stabilize the amplifier.
With a common emitter amplifier it's the emitter that is usually grounded.
A: When a signal is not amplified but simply taken from an emitter the reason is that the emitter will provide better current capabilities
I think you mean a common emitter amplifier, which is an amplifier of voltage. Emitter-follower or common collector amplifiers are used to match impedances, or to amplify power or current. The emitter-follower is a type of common emitter circuit that has a resistor between the emitter and ground. The output signal is taken from the point between the emitter and its resistor.
It is a good emitter, as you can not have a good absorber, which isn't a good emitter. Dark, Matt surfaces are good emitters and absorbers e.g. a saucepan.
The emitter resistor in a common emitter configuration provides negative feedback to the transistor, reducing both its voltage gain and distortion.
The very word emitter explains this. Emitter needs more carriers to get emitted by it. Hence doping has to be heavy.
Emitter
A common emitter BJT transistor has the emitter ground. So u measure input voltage at base with respect to the ground, i.e; emitter and also u measure the output voltage at collector with respect to the ground, i.e; emitter. Hence, the emitter is common and thus the name.
In the common emitter configuration, a class A amplifier, an increase in base voltage (the input) leads to an increase in base-emitter current which leads to a proportionately larger increase in base collector current. That pulls the collector towards the emitter, which decreases the collector voltage. Since the collector is the output, this configuration is an inverting amplifier.
A capacitor has lower resistance (impedance) as frequency increases. Adding an emitter capacitor effectively lowers the emitter resistance as frequency increases. Since gain in a typical common emitter amplifier is collector resitance divided by emitter resistance, this decrease in emitter resistance will increase gain as frequency increases.
The advantage of the emitter follower is that it has a positive gain of 1.
In a common emitter amplifier, the base-emitter current causes a corresponding collector-emitter current, in the ratio of hFe (beta gain) or collector resistance over emitter resistance, which ever is less. Since this ratio is usually greater than one, the differential collector current is greater than the differential base current. This results in amplification of the base signal. As you increase the base-emitter current, the collector-emitter current also increases. This results in the collector being pulled towards the emitter, with the result that the differential collector voltage decreases. This results in inversion of the base signal.