Search results
Results from the WOW.Com Content Network
Fig. 4 Top: Small-signal BJT cascode using hybrid-pi model Bottom: Equivalent circuit for BJT cascode using amplifier low-frequency parameters. The g-parameters found in the above formulas can be used to construct a small-signal voltage amplifier with the same gain, input and output resistance as the original cascode (an equivalent circuit).
Another major drawback is the amplifier's limited high-frequency response. Therefore, in practice the output often is routed through either a voltage follower (common-drain or CD stage), or a current follower (common-gate or CG stage), to obtain more favorable output and frequency characteristics. The CS–CG combination is called a cascode ...
This configuration is used less often than the common source or source follower.However, it can be combined with common source amplifiers to create cascode configurations. . It is useful in, for example, CMOS RF receivers, especially when operating near the frequency limitations of the FETs; it is desirable because of the ease of impedance matching and potentially has lower noi
A transconductance amplifier (g m amplifier) puts out a current proportional to its input voltage. In network analysis, the transconductance amplifier is defined as a voltage controlled current source (VCCS). These amplifiers are commonly seen installed in a cascode configuration, which improves the frequency response.
In analog amplifiers this curtailment of frequency response is a major implication of the Miller effect. In this example, the frequency ω 3dB such that ω 3dB C M R A = 1 marks the end of the low-frequency response region and sets the bandwidth or cutoff frequency of the amplifier.
Common-emitter amplifiers are also used in radio frequency circuits, for example to amplify faint signals received by an antenna. [dubious – discuss] In this case it is common to replace the load resistor with a tuned circuit. This may be done to limit the bandwidth to a narrow band centered around the intended operating frequency.
The amplitude of ECG ranges from 0.3 to 2 mV for the QRS complex, which is used to determine the interbeat interval from which the frequency is derived. The typical requirements for the amplifiers to be used in ECG include: [1] Low internal noise (<2 mV) High Input Impedance (Z in > 10 MΩ) Bandwidth ranging from 0.16–250 Hz
In electronics, a common-drain amplifier, also known as a source follower, is one of three basic single-stage field-effect transistor (FET) amplifier topologies, typically used as a voltage buffer. In this circuit (NMOS) the gate terminal of the transistor serves as the signal input, the source is the output, and the drain is common to both ...