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A gain greater than one (greater than zero dB), that is, amplification, is the defining property of an active device or circuit, while a passive circuit will have a gain of less than one. [4] The term gain alone is ambiguous, and can refer to the ratio of output to input voltage (voltage gain), current (current gain) or electric power (power ...
For transistors, the current-gain–bandwidth product is known as the f T or transition frequency. [4] [5] It is calculated from the low-frequency (a few kilohertz) current gain under specified test conditions, and the cutoff frequency at which the current gain drops by 3 decibels (70% amplitude); the product of these two values can be thought of as the frequency at which the current gain ...
In electronics, a transimpedance amplifier (TIA) is a current to voltage converter, almost exclusively implemented with one or more operational amplifiers. The TIA can be used to amplify [ 1 ] the current output of Geiger–Müller tubes , photo multiplier tubes, accelerometers , photo detectors and other types of sensors to a usable voltage.
In electronics the amplification factor, or gain, is the ratio of the output to the input of an amplifier, sometimes represented by the symbol A F. In numerical analysis the amplification factor is a number derived using Von Neumann stability analysis to determine stability of a numerical scheme for a partial differential equation.
where is the voltage gain of the inverting amplifier (positive) and is the feedback capacitance. Although the term Miller effect normally refers to capacitance, any impedance connected between the input and another node exhibiting gain can modify the amplifier input impedance via this effect.
See Figure 2. The asymptotic gain model is a special case of the extra element theorem. Figure 2: Possible equivalent signal-flow graph for the asymptotic gain model. As follows directly from limiting cases of the gain expression, the asymptotic gain G ∞ is simply the gain of the system when the return ratio approaches infinity:
The input impedance is the current gain (β) divided by the transconductance. The output (collector) conductance is determined by the Early voltage and is proportional to the collector current. For most transistors in linear operation it is well below 100 μS .
The open-loop gain is a physical attribute of an operational amplifier that is often finite in comparison to the ideal gain. While open-loop gain is the gain when there is no feedback in a circuit, an operational amplifier will often be configured to use a feedback configuration such that its gain will be controlled by the feedback circuit components.