| 摘要 |
PURPOSE:To change a current amplification factor continuously, by providing plural transistors which have emitters and bases connected commonly respectively and have different current amplification factors. CONSTITUTION:Emitters and bases of two PNP transistors (TR)Q1 and Q2 are connected commonly respectively, and a variable resistance VR1 for setting a current amplificaton factor is connected between collectors of both TRs. An emitter common connection point E, a base common connection point B, and a collector terminal C of the TRQ1 are used as the emitter, the base, and the collector of a composite TR respectively. When current amplification factors of TRsQ1 and Q2 are denoted as beta1 and beta2(beta1<beta2) respectively, the variable resistance VR1 is varied from zero to the infinite to set the current amplification factor of the composite TR to an opional value between the minimum beta1 to a maximum (beta1+beta2)/2. |
