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With advances in power semiconductors, it became possible to output high voltage directly from the output stage of the amplifier. For example, in 1967 Crown International introduced the DC300 amplifier, which is capable of directly driving 70-volt lines, as well as traditional speaker loads, thanks to its overall power [5] of 500W. [6]
For example, if the meter is set to a range of 300 V full scale, the meter's impedance will be 6 MΩ. 20,000 Ω/V is the best (highest) sensitivity available for typical analog multimeters that lack internal amplifiers. For meters that do have internal amplifiers (VTVMs, FETVMs, etc.), the input impedance is fixed by the amplifier circuit.
It is also used in speed control of fans. Potentiometers operated by a mechanism can be used as position transducers , for example, in a joystick . Potentiometers are rarely used to directly control significant power (more than a watt ), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.
A feedback loop from the bridge amplifier output to the pre-amp input helps to eliminate any remaining contribution from the fundamental frequency. The output from these blocks is measured, typically using an instrumentation amplifier driving an analog or digital meter. The voltage at the meter is due to the harmonic distortion products plus noise.
They may be used to capture transient signals when operated in a single sweep mode, without the brightness and writing speed limitations of an analog storage oscilloscope. [ 4 ] The displayed trace can be manipulated after acquisition; a portion of the display can be magnified to make fine detail more visible, or a long trace can be examined in ...
In about 1936 and 1937, German broadcasters developed a peak programme meter with a mirror galvanometer known as a "Lichtzeigerinstrument" (light pointer) for the display. The system consisted of a drive amplifier (e.g., ARD types U21 and U71) and a separate display unit (e.g., ARD types J47 and J48). [9]
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Line level is the specified strength of an audio signal used to transmit analog sound between audio components such as CD and DVD players, television sets, audio amplifiers, and mixing consoles.