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Audio level meter (VU Meter):
This circuit uses just one IC and a very few number of external components. It displays audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses analog
voltage levels and drives ten LEDs providing a logarithmic 3 dB/step analog display. LED current drive is regulated and programmable, eliminating need for current limiting resistors. The IC contains an adjustable voltage reference and an accurate ten-step voltage
divider. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of positive supply. Furr, it needs no protection against inputs of ±35V. The input buffer drives 10 individual comparators referenced to precision divider. Accuracy
is typically better than 1 dB. (added 9/06) |
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Audio Level Meter: (diagram
added 6/03) |
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Audio Tone Control: (circuit added 7/02) |
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Automatic Loudness Control: Simple add-on module Switchable
"Control-flat" option (added 3/05) |
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Bass-Treble Tone Control
Circuit: The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control
of bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a Zener regulated supply provided on circuit. Each tone response is defined by a
single capacitor chosen to give desired characteristic.….. (added 6/06) |
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Better Volume Control: how to create a log pot
that is better than "real" thing (added 4/02) |
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Build a Simple Soft Action Muting Switch: 10/14/04
EDN-Design Ideas / (added 10/05) The circuit in Figure 1 adds a soft muting switch with power-up/power-down muting to a line-level audio circuit. R4, C1, and JFET Q1 quietly ground a signal in 100 to 200 msec when you close S1 or release it when you open S1.
Potentiometer R2, set to twice Q1's cutoff voltage, makes on/off transition.... |
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Designing with the LMC835 Digital Controlled Graphic Equalizer:
National Semiconductor Application Note 04-Nov-1995 (app note added 4/02) |
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Digital Delay Unit for Surround Sound: (schematic /
circuit design added 9/02) |
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Digital Volume Control has Log Taper: 04/11/02 EDN
Design Ideas / (added 12/04) Digital potentiometers provide a compact and convenient way to attenuate audio-amplifier signals. However, most such potentiometers suffer from at least one flaw: a nonlogarithmic step increment. To avoid this problem, a user
must usually step the potentiometer in a nonlinear sequence to simulate a logarithmic taper. ... |
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Digital Volume Control: based on DS1669 Digital
Pot IC (added 5/02) |
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Dual Channel Digital
Volume Control: (electronic Circuit / Schematic added 10/04) |
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Easy Parametric and Graphic Eq's Plus Peaks and
Notches: (electronic circuit added 8/02) |
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Generating Tone using Pdo: Toshiba 870X
Series Application Note (app note added 2/06) |
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Guitar Control: CaStand-alone, 9V battery powered unit .
Three-level input selector, three-band tone control (added 3/05) |
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