Amplifiers Objectives Part 02
21 . A push pull amplifier is biased in Class B .
22 . An IGFED is a square law device.
23 . Class A amplifier has least distortion.
24 . In a resistance loaded amplifier, the gain decrease at higher frequency with decreasing reactance of the stray CT.
25 . In an amplifier the collector voltage equals to full V* of 28 V instead of normal 12 V because of RE is open.
26 . In a resistance loaded amplifier, the gain decrease at low frequency because of increasing resistance of CC.
27 . Class A amplifier is used when minimum distortion is desired.
28. In an ideal op-amp the output impedance is Zero.
29 . The bandwidth of an audio amplifier extends from 20 to 20,000 Hz.
30 . The noise figure F of amplifier is defined as (F = 10 log10Si / Ni
So / No
31 . The gain of an amplifier with feedback is given by the relation A/
1 – BA
32 . An ideal voltage amplifier should have (Ri = infinite, R0 = 0).
33 . An ideal current amplifier should have (Ri = 0, R0 = infinite).
34 . Non linearity in active device contributes to harmonics distortion in amplifiers.
35 . In logarithm amplifiers, output voltage is equal to input voltage.
36 . Logarithm amplifiers used in dividers.
37 . Radio Frequency amplifiers used a variable capacitor tuning.
38 . In high frequency region, an amplifier behaves like a low pass filter.
39 . Cascode amplifier will be preferred for highest gain.
40 . A cascaded amplifier will have higher cut-off frequency less than that of single stage amplifier.