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An F1 hybrid (or filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where it may appear as F1 crossbreed. The term is sometimes written with a subscript, as F1 hybrid.
Best Answer: The 'h' (lower-case) stands for 'hybrid model'. Transistor amplifiers may be modeled as 2-port devices with 1 port being the 'input' and the other port the 'output'. Any 'black box' 2-port device has sets of parameters that can be used to describe the electrical characteristics of what's inside the box. One type of these parameters is called the hybrid set, or h parameters. For the common-emitter bi-polar junction transistor amplifier h21 is called hfe. 'h' is for hybrid, 'f' is for 'orward, 'e' is for common Emitter. The difference between hFE and hfe is: FE is for a fixed DC bias and a fixed DC current gain (and that must be specified for each value of hFE).