Positive SSL
1 如圖所示,變壓器耦合級放大電路,N1:N2 = 5:1、N3:N4 =2:1、AV1 = 50、AV2 = 100、AV3 = 20,則此電路之總電壓增益為多少?
A 60dB
B 80dB
C 120dB
D 160dB

變壓器電壓與匝數成正比

`A_(VT)` = `50*1/5*100*1/2*20`

= 10000

`A_(VT)(dB)`= 20 log 10000

= 20 *4 = 80 dB