On the presented circuits an important capacitor is missing, the source input cc decoupler.As in this circuit the input is directly connected to a op-amp, input decoupling is a must.Risks are eventual continuous current coming from the source blows the LM386 IC, or worst case a problem with this amplifier circuit, causing continuous current flowing to the source, makeing hot-dogs of your connected smart phone. ;-)Never forget to decouple audio inputs.In this case 10µF 25V with negative pole connected to pin 3 of LM386 and a 1KOhm resistor from ground to the same pin will suffice.
Basic Amplifier Circuit Pdf Free
Can you build a more powerful stereo amplifier with at least 4 microphone inputs and with ability to play mp3 music files from a pen drive. There must a mixing circuit to mix the pen drive music with the microphone inputs in such a way that we can sing a song with the instrumental music playing from the pen drive. If a bass treble mid circuit can be added, it will be a wonderful amplifier every home should possess. The amp should have three modes of working. In one mode, we will be able to play a song from the pen drive. In mode 2 we can speak through the microphone. In mode 3 we can sing along with the music playing from the pen drive. Buying such an amplifier from the shop will be very expensive. But if we can make one circuit for this, it will be very good and inexpensive. I request all the readers of this forum to contribute your ideas to this project. Thank you
An operational amplifier (often op amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output.[1] In this configuration, an op amp produces an output potential (relative to circuit ground) that is typically 100,000 times larger than the potential difference between its input terminals. The operational amplifier traces its origin and name to analog computers, where they were used to perform mathematical operations in linear, non-linear, and frequency-dependent circuits.
Op amps are used widely in electronic devices today, including a vast array of consumer, industrial, and scientific devices. Many standard integrated circuit op amps cost only a few cents; however, some integrated or hybrid operational amplifiers with special performance specifications may cost over US$100 in small quantities.[2] Op amps may be packaged as components or used as elements of more complex integrated circuits.
Sourced by many manufacturers, and in multiple similar products, an example of a bipolar transistor operational amplifier is the 741 integrated circuit designed in 1968 by David Fullagar at Fairchild Semiconductor after Bob Widlar's LM301 integrated circuit design.[12] In this discussion, we use the parameters of the hybrid-pi model to characterize the small-signal, grounded emitter characteristics of a transistor. In this model, the current gain of a transistor is denoted hfe, more commonly called the β.[13]
The use of op amps as circuit blocks is much easier and clearer than specifying all their individual circuit elements (transistors, resistors, etc.), whether the amplifiers used are integrated or discrete circuits. In the first approximation op amps can be used as if they were ideal differential gain blocks; at a later stage limits can be placed on the acceptable range of parameters for each op amp.
A basic circuit is designed, often with the help of circuit modeling (on a computer). Specific commercially available op amps and other components are then chosen that meet the design criteria within the specified tolerances at acceptable cost. If not all criteria can be met, the specification may need to be modified.
Another typical configuration of op-amps is with positive feedback, which takes a fraction of the output signal back to the non-inverting input. An important application of it is the comparator with hysteresis, the Schmitt trigger. Some circuits may use positive feedback and negative feedback around the same amplifier, for example triangle-wave oscillators and active filters.
The non-inverting input of the operational amplifier needs a path for DC to ground; if the signal source does not supply a DC path, or if that source requires a given load impedance, then the circuit will require another resistor from the non-inverting input to ground. When the operational amplifier's input bias currents are significant, then the DC source resistances driving the inputs should be balanced.[16] The ideal value for the feedback resistors (to give minimal offset voltage) will be such that the two resistances in parallel roughly equal the resistance to ground at the non-inverting input pin. That ideal value assumes the bias currents are well matched, which may not be true for all op amps.[17]
1962: An op amp in a potted module. By 1962, several companies were producing modular potted packages that could be plugged into printed circuit boards.[citation needed] These packages were crucially important as they made the operational amplifier into a single black box which could be easily treated as a component in a larger circuit. 2ff7e9595c
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