Free electronic circuit design and schematic diagram
Unlike the 10-band graphic equalizer in our previous circuit that use a gyrator circuit, this 3-band graphic equalizer circuit uses Baxandall topology, similar with the Baxandall tone control but with additional mid frequency control. The figure below shows the schematic diagram of the circuit. The operational amplifier employ an LF351 IC chip, but any low noise op-amp will be suitable […]
Read more
For battery operated devices, this class D amplifier is suitable because its high efficiency (85%) helps extend the battery life. In the internal circuitry, a boost converter with over 90% efficiency is provided to step-up the voltage supply, and need only one external inductor as the additional component for this function. When driving 8 ohm loud speaker, this class-D amplifier […]
Read more
This class-D audio power amplifier is suitable for TV and home stereo set. TDA7882 IC chip provides class-D audio power amplifier solution. Since this chip has only mono channel, you need two pieces of this circuit for stereo application. The power supply voltage is flexible, accept (+-)10V to (+-)25V. This circuit needs a split supply (symmetric power supply). Here are […]
Read more
The combination of class D amplifier controller LM4651and power MOSFET package LM4652 gives compact and robust high efficiency class D power amplifier solution. This circuit is ideal for car booster amplifier, active speaker/subwofer, home theater, or PC’s multimedia sound system. The maximum efficiency 85% is obtained at 125W power output condition. The total harmonics distortion is 10% at full power […]
Read more
The simple low-pass filter is shown in Figure below. The filter has a 20dB/decade roll-off after its corner frequency fc. Its low-pass frequency gain (f->0) is defined by R3/R1. This allows low-frequency gains other than unity to be obtained. R2 should be chosen equal to the parallel combination of R1 and R3 to minimize error due to bias current. LMV721/722 […]
Read more
The LM1894 is a stereo noise reduction circuit suitable for audio playback application. The DNR system is non-complementary, meaning that it does not require encoded source signal. The system is compatible with almost all prerecorded tapes and FM broadcasts. This noise reduction system uses psycho-acoustic masking and an adaptive bandwidth filtering to achieve 10 dB noise reduction. This DNR would […]
Read more
Using this circuit, you can measure the actual output power of your amplifier. You can put this circuit in a box as a measurement instrument, or you can integrate it inside your power amplifier to get real power display. The circuit’s schematic diagram is shown in the figure below. This circuit would be a handy instrument for audio engineer, for […]
Read more