High-frequency small-signal equivalent model of transistor
The high-frequency small-signal equivalent circuit of the transistor has two main representation methods: Physical model equivalent circuit: mixed parameter equivalent circuit.
Network parameter equivalent circuit: y parameter equivalent circuit.
A mixed parameter equivalent circuit
Note: The existence of C b'c and rbb 'is very detrimental to the high-frequency use of transistors.
Cb'c feedbacks the output AC current to the input, which may cause the amplifier to self-excite.
rbb 'will cause high frequency load feedback in the common base circuit, reducing the current amplification factor of the transistor.
Fiber optic adapters are typically used to connect two fiber optic cables together. They come in versions to connect single fibers together (simplex), two fibers together (duplex), or sometimes four fibers together (quad). Adapters are designed for multimode or single-mode cables. The single-mode adapters provide more precise alignment of the tips of the connectors and can be used to connect multimode cables. The reverse is not suggested as this might cause misalignment of the small single-mode fibers and loss of signal strength (attenuation).
Optical attenuators are commonly used in fiber-optic communications, either to test power level margins by temporarily adding a calibrated amount of signal loss, or installed permanently to properly match transmitter and receiver levels. Sharp bends stress optic fibers and can cause losses. If a received signal is too strong a temporary fix is to wrap the cable around a pencil until the desired level of attenuation is achieved. However, such arrangements are unreliable, since the stressed fiber tends to break over time.
Types:
Optical attenuators can take a number of different forms and are typically classified as fixed or variable attenuators. What's more, they can be classified as LC, SC, ST, FC, MU, etc. according to the different types of connectors.
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Fiber Optic Attenuator
Optical Fiber Attenuator,Fiber Optic Attenuator,Fiber Optic Fixed Attenuator,FC Fiber Attenuator
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