Transistor Amplifier Circuits Unit 7 – RC Coupling
Exercise 3 – Frequency Response
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to determine the frequency response of
an RC-coupled amplifier by using measured values. You will verify your results with a
multimeter and an oscilloscope.
DISCUSSION
- Amplifier gain varies as the input signal frequency varies. This behavior is referred to as the
frequency response. - The amplifier circuit used in this exercise experiences decreases in gain at frequencies below
20 Hz and above 100 kHz. - The bandwidth of an amplifier is the range of input signal frequencies over which the
amplifier gain remains constant. - In general, a 15% decrease in amplifier gain indicates that the amplifier is at the end of its
bandwidth range. - Frequency response curves for audio amplifiers should be relatively flat between 20 Hz and
20 kHz. - The coupling capacitor value may affect frequency response (at the lower frequencies) of the
amplifier. - Upper limit frequency bandwidth is affected by the frequency-dependent transistor
parameters and the stray capacitance of circuit elements.