Content deleted Content added
m →Distributed resistance: ref format |
m →Active components: ref format |
||
Line 143:
Distributed elements are passive, but most applications will require active components in some role. A microwave [[hybrid integrated circuit]] uses distributed elements for many passive components, but active components (such as [[diode]]s, [[transistor]]s, and some passive components) are discrete. The active components may be packaged, or they may be placed on the [[Substrate (electronics)|substrate]] in chip form without individual packaging to reduce size and eliminate packaging-induced [[Parasitic element (electrical networks)|parasitics]].<ref>Bhat & Khoul, pp. 9–10, 15</ref>
[[Distributed amplifier]]s consist of a number of amplifying devices (usually [[FET]]s), with all their inputs connected via one transmission line and all their outputs via another transmission line. The lengths of the two lines must be equal between each transistor for the circuit to work correctly, and each transistor adds to the output of the amplifier. This is different from a conventional [[multistage amplifier]], where the [[Gain (electronics)|gain]] is multiplied by the gain of each stage. Although a distributed amplifier has lower gain than a conventional amplifier with the same number of transistors, it has significantly greater bandwidth. In a conventional amplifier, the bandwidth is reduced by each additional stage; in a distributed amplifier, the overall bandwidth is the same as the bandwidth of a single stage. Distributed amplifiers are used when a single large transistor (or a complex, multi-transistor amplifier) would be too large to treat as a lumped component; the linking transmission lines separate the individual transistors.<ref>Kumar & Grebennikov, pp. 153–154</ref>
== History ==
| |||