Sound pressure meter

admin April 7, 2010 3 Comments
Description. Here is a simple circuit that can be used to check the sound levels.The sound pressure meter is vey useful in setting up home theater systems , if you need to test the sound pressure of each channels on different positions in the room. The circuit is nothing but a non- inverting amplifier based on op-amp CA 3140 9 (IC1).The sound picked by the condenser mic will be amplified by the IC1 and rectified by the bridge D1...
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Speech amplifier circuit.

admin April 7, 2010 10 Comments
Description. This circuit given here can be housed in the box containing the speaker to form a handy microphone amplifier.The device can be used by teachers,guides,lecturers etc for speaking in a crowdy or noisy environment. The circuit is designed base on the audio power amplifier IC TDA 7052.The IC can deliver a maximum power output of 1.2 W at a 6V supply.The audio signal from the microphone is pre amplified by the amplifier based on Q1 (BC 547) and...
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Sound shifter circuit

admin April 7, 2010 1 Comment
 Description. Here is superb sound shifter circuit that can be used to add effects to the input sound signal.The circuit is ideal for incorporating in toys and adds great fun.The circuit can be also used in mixers and recorders. The circuit is based on IC HT 8950 from Holtek. The IC HT8905 is a single chip CMOS sound modulator IC which produces seven steps of shift in the frequency of the given sound.This producing a dramatic change in the...
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3 Band graphic equalizer circuit.

admin April 7, 2010 14 Comments
Description. Here is a simple 3 band graphic equalizer circuit  made of a single op amp IC LF351 (IC1) and few passive components.The component values of this circuit are not very critical and can be replaced with nearest values with a little loss on the performance.This feature make it easy to be assembled from your junk box. The opamp LF351 is wired to operate in three frequency ranges-  high,medium and low.The circuit is designed such that the circuit produces...
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50 W transistor amplifier

admin April 7, 2010 37 Comments
Description.  A very rugged and reasonably power amplifier circuit that can be used  for any audio applications. The amplifier produces 60W rms at 50V supply  on a 8 Ohm load.The circuit is designed such that most of the components are not critical and can be easily replaced by nearest values.This make it ideal to assemble from your electronics junk box.  The capacitor C1 controls low frequencies and capacitor C2 controls high frequencies.The circuit ia basically a class B amplifier.The...
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Low cost amplifer.

jacky March 8, 2012 6 Comments
Description. No big deal here! You can make a decent power amplifier using just three transistors. All components used here can be obtained from your electronic junk box. Also you just need a 9V transistor radio battery to power this circuit. The circuit is ideal for a pocket radio or other hand held audio equipments. The first part of the circuit here is a preamplifier consisting of transistor Q1(2N2222). The collector of the Q3 is coupled to the base...
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Converting CD-ROM drive to audio CD player

admin March 8, 2012 7 Comments
Description. Here is the simplest scheme for converting a CD ROM drive of your computer to a Audio CD player. The minimum requirement for the player is that, it should have a audio output and skip button. Luckily most of the CD ROM’s are equipped with both of these.  The CD ROM drive needs two voltages, 12V & 5V for its operation. So the main objective is to build a suitable power supply for the CD ROM drive. The...
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IR Headset

admin March 7, 2012 21 Comments
Description. Here is a simple IR headphone circuit that is suitable for listening to TV or radio with out disturbing others. For beginners the IR headset is a better option than FM head sets because they often produce desirable sound quality with out tuning as well as difficult impedance matching that is often done  in  radio circuits which is difficult for beginners. Transmitter.  The audio signal is coupled to the base of T1 (BC547) by an audio transformer. The...
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3 W Stereo amplifier using MAX 7910

admin January 24, 2012 4 Comments
Description. A straight forward circuit diagram of a 3W stereo amplifier circuit using MAX 7910 IC is given here. This circuit is ideal for small power audio applications like portable CD players or radio sets. The circuit is designed strictly as per the datasheet and found to be working great. The MAX9710  a stereo audio power amplifier IC capable of delivering  3Watts  of out put to 4 Ohm loads. MAX9710 can be operated from a  single 4.5V to 5.5V...
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Audio level meter circuit

admin February 28, 2011 2 Comments
Audio Level Meter Description A simple and low cost audio level meter circuit that can be used to measure the audio level of your sound source.This circuit is a valuable tool for those who are interested in audio circuits. The circuit is designed with a flat frequency response in the range of  20Hz to  50Khz. Input sensitivity is 100mV for a FSD on a 100uA ammeter.The circuit is build based on on two common emitter amplifiers, the first stage...
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