This simplified formula, the 20 log rule, is used to calculate a "'voltage gain "'in decibels and is equivalent to a power gain only if the impedances at input and output are equal.
42.
The voltage gain depends almost exclusively on the ratio of the resistors R _ { \ text { C } } / R _ { \ text { E } } rather than the transistor's intrinsic and unpredictable characteristics.
43.
Those other designs offer lower voltage gain ( traded off for higher plate current ) than the 12AX7 ( which has a voltage gain or A _ v of 100 ), and are more suitable for high-frequency applications.
44.
Those other designs offer lower voltage gain ( traded off for higher plate current ) than the 12AX7 ( which has a voltage gain or A _ v of 100 ), and are more suitable for high-frequency applications.
45.
Output impedance " Z " of a transformerless circlotron where each stage is a single triode with plate impedance of " R p " and voltage gain of " ? " is defined by the formula
46.
Current limiting for Q20 is performed in the voltage gain stage : Q22 senses the voltage across Q19's emitter resistor ( 50 & Omega; ); as it turns on, it diminishes the drive current to Q15 base.
47.
In low-frequency circuits, a high voltage gain is typically desired, hence the importance of using a load with resistance " R L > > R out " to avoid attenuation of the signal reaching the load.
48.
Nonetheless, the voltage gain is appreciable even for small loads : according to the table, with " R S = r E " the gain is " A v = g m R L / 2 ".
49.
The S-parameters then take on a more intuitive meaning such as the forward voltage gain being defined by the ratio of the forward voltages S _ { 21 } = V _ 2 ^ + / V _ 1 ^ +.
50.
If the cathode resistor is unbypassed, negative feedback is introduced and each half of a 12AX7 provides a typical voltage gain of about 30; the amplification factor is basically twice the maximum stage gain, as the plate impedance must be matched.
