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The operational amplifier


The operational amplifiers built a few dozen transistors attached to direct amplification circuits with high voltage. Often referred to as “op-amp”. Their properties vary widely depending on the model. Balanced inputs and outputs are usually asymmetric, high input resistance and very low output resistance. One of them is typical linearity and low cut-off frequency.

According to their structure can be constructed of discrete components or integrated circuits. The operational amplifier are historical reasons for designation, since this type of circuit during WWII analog computer developed.

The operational amplifiers are widespread low price, and because of the large range of adjustable characteristics. You can find DC and AC voltage amplifiers, mixers, measuring instruments, vibration generator in regulatory technical circuits and so on. Some of monolithic or hybrid technology implemented special type of very high quality (fast, high-voltage, low noise with good input characteristics), priced accordingly higher.


The operational amplifier basics


The op amp input stage is a differential amplifier located.
A “-” marked input is called inverting input and phase reverse, since this input voltage, supplied to the output reverse polarity and a phase of 180 ┬░ is displayed. The amplifier is connected to the inverting input voltage amplifies and inverts.
The input “+” marked, or non-inverting input phase is called non-translator, as the applied voltage polarity identical and the same phase position is outputted. The non-inverting amplifier coupled to the input voltage is amplified, but no inversion.

Basic example is a operational amplifier circuit used in many places:


Non inverted operational amplifier with TL072.
Non inverted op amp

The R1, R2, R3 resistance with minimal positive voltage. This circuit is used as the Klon Centaur.

Inverting op amp circuit in example:

Inverted opamp operationak amplifier with TL072. Klon Centaur preamplifier.
Inverted op amp circuit

We use operational amplifiers with different properties: LM741, TL062 TL072, TL074, TL082, JRC4558.


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