DC CONTROL OF NATIONAL 3D-SOUND AND

LOUDNESS CONTROL

Figure

Figure 16 shows a possible circuit if electronic control

of these functions is required. The typical DC level at pins 3

and 22 is 7.5V (V

posed, and this can be used to gias a FET switch as shown

to save components. For switching with a 0V - 5V signal a

low-threshold FET is required when using a 12V supply.

With larger switching levels this is less critical.

The high impedance PNP base input of the loudness control

pin 9 is readily switched with a general purpose NPN

transistor.

DS101125-37

FIGURE 16. Application Circuit with Electronic Switching

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