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low frequency gain will be 20log(Vo/Vin)
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∙ 11y ago
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What is amplifier and what is the general circuit of amplifier?
An amplifier amplifies voltage or current. The most basic amplifier consists of a transistor where a signal is fed into the base and is output to the emitter or collector. For simple, low frequency applications (not RF), it may be simpler to use an operational amplifier (op amp) than designing your own amplifier. Also, the data sheets provide very helpful schematics for creating an amplifier. A very common one is the 741; these are also fairly cheap.
Why gain increases in low frequency region in BJT?
Because Beta (current gain) in a transistor is inversely proportional to frequency. Hence it increases as frequency decreases. Also the ac voltage gain is directly proportional to Beta.
Why do amplifiers have high voltage gain?
If you got a microphone that converts soft acoustic waves to audio voltage, the low output must be amplified. For that purpose it is good to have an amplifier with high voltage gain. The same is needed for the output of your CD player before it goes to the power amp. Scroll down to related links and look at "Amplification". Many amplifiers do not need high voltage gain. The final output stage of a good power amplifier usually has high current gain but very low voltage gain. Amplifiers are also used as mixers and filters where there is no voltage gain.
What is opamp?
An operational amplifier, which is often called an op-amp, is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output.[1] An op-amp produces an output voltage that is typically millions of times larger than the voltage difference between its input terminals.Typically the op-amp's very large gain is controlled by negative feedback, which largely determines the magnitude of its output ("closed-loop") voltage gain in amplifier applications, or the transfer function required (in analog computers). Without negative feedback, and perhaps with positive feedback for regeneration, an op-amp essentially acts as a comparator. High input impedance at the input terminals (ideally infinite) and low output impedance at the output terminal(s) (ideally zero) are important typical characteristics.Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. Many standard IC op-amps cost only a few cents in moderate production volume; however some integrated or hybrid operational amplifiers with special performance specifications may cost over $100 US in small quantities. Op-amps sometimes come in the form of macroscopic components, (see photo) or as integrated circuit cells; patterns that can be reprinted several times on one chip as part of a more complex device.The op-amp is one type of differential amplifier. Other types of differential amplifier include the fully differential amplifier (similar to the op-amp, but with two outputs), the instrumentation amplifier (usually built from three op-amps), the isolation amplifier (similar to the instrumentation amplifier, but which works fine with common-mode voltages that would destroy an ordinary op-amp), and negative feedback amplifier (usually built from one or more op-amps and a resistive feedback network).
What does a comparator do in electronics?
A comparator is an operational amplifier used without a feedback circuit. The output of the comparator will be high when the voltage of the non-inverting input is below the inverting input, and low when the inverting is above the non-inverting input. The output is undefined - i.e. can by anything - when the voltages are equal.
What are the disadvantages of operational amplifier?
IT has very low gain. this is the biggest disadvantage. Thank You.
Frequency response curve of RC coupled amplifier?
at low frequency less than 50hz the voltage gain decreases with decreasing frequency and at mid frequency{50hz to 20khz} the voltage gain is uniform because resistor value are independent of frequency change and at the high frequency votage gain falls.
What is a common base NPN amplifier?
A common base NPN amplifier is used for high frequency applications as the base minimize oscillations at high frequency, separates the input and output. In a common base NPN amplifier the voltage gain is high, relatively low input impedance and high output impedance compared to the common collector.
What is amplifier and what is the general circuit of amplifier?
An amplifier amplifies voltage or current. The most basic amplifier consists of a transistor where a signal is fed into the base and is output to the emitter or collector. For simple, low frequency applications (not RF), it may be simpler to use an operational amplifier (op amp) than designing your own amplifier. Also, the data sheets provide very helpful schematics for creating an amplifier. A very common one is the 741; these are also fairly cheap.
What is the meaning of gain in an amplifier or operational amplifier. Is high gain or low gain is what we try to achieved?
There are many uses for amplifiers. Some try to achieve extremely high gain such as in a radio receiver. Many try to achieve no overall gain. Examples include mixers and filters. Some only try to achieve limited gain. Oscillators try to achieve zero gain at most frequencies but unity to very high gain at the frequency of oscillation depending on the output wave form required. Basically - everything in electronics is an amplifier. The absolute gain of am amplifier is the ratio of output signal to input signal. For voltage or current amplifiers this is usually expressed as field decibels which is 20 log (out/in). For power amplifiers the gain in decibels is 10 log (output power/input power). If the gain is less than one, the same rules apply but the decibels will turn out to be a negative quantity.
Why electrolytic capacitors are used for frequency response of BJT as amplifier?
It can take a lot of capacitance to present a low impedance to a low frequency. Electrolytics offer lots of capacitance for a low price.
What should I do to install a low pass filter if my amp doesnt have one?
A: Installing a low pass filter is only required if the frequency are not there or to eliminate the low frequency, If it is an audio amplifier you never will need low frequency since your mine hears cannot hear those frequency.
Why do you need small signal amplifier?
Small signal amplifier is needed because it is used for amplifying input signals having low frequency or amplitude.
How do you convert low frequency to high frequency with a circuit?
You typically create a DC power supply from the low frequency, and use that to run a high frequency oscillator and amplifier. If there needs to be a relationship between frequency in and frequency out, often there is a divider running on the high frequency side in combination with a phase locked loop synching up to the low frequency side.
Why the gain of pnp transistor is low?
it doesn't have to be. depends on design of amplifier using transistor.
Frequency response of bjt amplifier?
All amplifier typically exhibit a band-pass frequency response. The cut off frequency in the low end is usually determined by the coupling band bypass capacitor .and the high frequency limit is typically determined by internal capacitances in the transistor itself.
What is the effect of low frequency on the voltage?
The frequency would decrease the gain and increase the output voltage
