Free electronic circuit design and schematic diagram
This circuit can be applied in digital-controlled audio application, for example to select the active input line by a micro controller. For such purpose, we can build three units of this circuit and feed their outputs into a three channel simple audio mixer circuit, and now the selection of the active channel can be done by a micro controller. For […]
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Some costly efforts have been made to shorten the waiting time for all kind of services in the call center or other business, but many customers still complaining about the long waiting time, so other solution should be taken to handle this situation. Waiting a call hold can be boring if there is only silence on the line, that’s the […]
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Using the circuit shown in the schematic diagram below, we can control the low-level audio signals with ±3V variable DC voltage. This attenuator circuit uses a field effect transistor (FET) to shunt the signal to ground. The R2 is used to control the output level (the attenuation level), but you can use other source of voltage signal to control the […]
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Using circuit shown below, we can invert or amplify without inversion by flipping a switch. The voltage gain is depending on the switch position. It could be either +1 or -1. The variation of the circuit comes in two version, A and B. I personally prefer B version, since there is no moment when the noninverting input voltage level is […]
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The device below is built as an active stereo-tone/volume control for TV receivers, car radios and mains-fed equipment. The device below has function for bass and treble control, volume control with built-in contour (can be switched off) and balance. We can control all these function using dc voltages or by single linear potentiometers. This device has 4 features. The features […]
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High-end audio equipments are normally digitally controlled by a a microprocessor (microcontroller) system. It’s necessary to have digital interface that provide control for audio signal switching, as well as programming the gain to control the signal volume. TEA6320 comes with the solution for digital control of audio source channel selector and volume control, very useful integrated circuit for modern audio […]
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As shown in a schematic diagram below, this circuit implementation of phase shifter circuit is well suited to using digital potentiometer to control the resistive control element of the phase shifter. The phase at a given frequency is now under control of a digital signal using this circuit which is optimized for phase-shifting over the audio range. By using a […]
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