Electronic Circuits and Diagram-Electronics Projects and Design

Description. LM4880 is HiFi dual audio amplifier IC from National Semiconductors. This IC is specifically designed to produce high quality audio output with a minimum number of external components.LM4880 is capable of delivering 250mW per channel into an 8 ohm load. The IC has 0.1% THD and has a supply voltage range of 2.7 to 5V DC. In the circuit shown below, resistors R1 and R2 are feedback resistors.C4 and C5 are input DC decoupling capacitors. Capacitor C3 provides power supply filtering and thereby reduces noise. The amplifier automatically shut downs when a logic high is given to the shutdown…

Stereo sound level meter / Stereo VU meter Description. The circuit shown here is of a stereo sound level indicator/VU meter  using the IC TA7666P from Toshiba. The TA7666P consists of 2 inverting amplifiers, ten comparators and a reference voltage generator. The turn on levels for TA7666P are 5dB, 5dB, 3dB, 3dB and has a supply voltage range between 6 to 12V DC. The IC has low quiescent current and has variable voltage gain. In the circuit R11 and R12 are used to set the voltage gain while C1 and C4 are decoupling capacitors. R1 to R10 limits the current…

Description. Here is the circuit diagram of a simple 3 channel audio splitter based on the IC NE5532. NE5532 is a dual internally compensated low noise opamp from Fairchild semiconductors. It has a high small signal and power bandwidth, making it well suitable for high quality audio applications. Here the IC1 is wired as a non inverting amplifier with a gain 3.The audio signal to be splited is applied to the non inverting pin of IC1 through the POTs R2 and R3.Capacitor C2 works as a DC decoupler and resistors R8, R9, R10 splits the output of the IC1 into…

Description. Many low pass filter circuits for subwoofer are given here and this is just another one. The circuit given here is based on the opamp TL062 from ST Micro electronics. TL062 is a dual high input impedance J-FET opamp which has very low power consumption and high slew rate. The opamp has excellent audio characteristics and is very suitable for this circuit. Out of the two opamps inside TLC062, first one is wired as the mixer cum pre amplifier stage. The left and right channel are connected to the inverting input of IC1a for mixing. The gain of first…

Description. This is just another 20W audio amplifier circuit , but this time based on the LM1875 audio amplifier IC from National Semiconductors. With a 25V dual power supply LM1875 can deliver 20W of audio power into a 4 ohm speaker. The LM1875 requires very less external components and has very low distortion. The IC is also packed with a lot good features like fast slew rate, wide supply voltage range, high output current, high output voltage swing, thermal protection etc. The IC is available in TO-220 plastic power package and is well suitable for a variety of applications like…

Description The audio amplifier shown here is based on the TDA7240 IC from ST Microelectronics. The TDA 7240 is an integrated audio amplifier IC that can deliver 20 watts of audio output power into a 4ohm load. The IC has minimum external parts count and is available in the 7 pin compact Heptawatt package. The IC also has a lot of good features like loud speaker protection, short circuit protection, low noise, low distortion etc. The circuit can be operated from a 12V DC single power supply and this makes it very useful in car audio applications. Circuit diagram. Notes….

Description. Here is the circuit diagram of an excellent stereo preamplifier with tone control using the IC TDA1524 from Phillips. The IC requires very few external components, has very low noise and has a wide power supply voltage range.  POTs R1 to R4 can be used for controlling the volume, balance, bass and treble respectively. LED is D1 is a power ON indicator and R1o is its current limiting resistor. Circuit diagram. Notes. Assemble the circuit on a good quality PCB. Switch S2 is the ON/OFF switch. Swich S1 can be used to select linear or contour mode. Supply voltage…

Description. The circuit diagram shown here is of a 2 x 60 Watt stereo amplifier based on the LM4780 from National Semiconductors. LM4780 is a superb audio amplifier IC capable of delivering 60W Rms power output / channel into 8 ohm speakers. The LM4780 has very low total harmonic distortion (less than 0.5% at full output) and has a power supply rejection ration (PSRR) of 85 dB. The IC requires very few external components and has a built in mute facility. The LM4780 is completely protected using their trademark SPiKe technology and has a signal to noise ratio greater than…

This versatile amplifier circuit is designed and submitted by Mr Seetharaman Subramanian from Chennai . The full credit of this article goes to him and we are very proud to publish this fabulous circuit here. Seetharaman’s description about the circuit. This concept has appeared long back in Practical Electronics a UK based Magazine. Based on this concept I designed this circuit during 1981 to 1986 with lots of field trials and modifications, the design was frozen in 1986. I have assembled so many amplifiers for me and for my friends based on this design with various power levels. They are…

Decription. The circuit given here is of a three input mic mixer cum preamplifier using the IC LM348. The LM348 is a high gain, internally compensated quad operational amplifier with a class AB output stage. The IC has very low input supply current drain (0.6mA/ opamp) and operates from a dual power supply. Out of the four op-amps inside the IC LM348, IC1a, IC1b and IC1c are wired as non inverting amplifiers and they serve as the input amplifiers for the corresponding mic channels. The output of these three amplifiers are tied together and connected to the inverting input of…