Analog electronics is one of the most importantsections of electrical engineering, which has become a stepping stone for the transition from resistors, rheostats and ammeters to digital "measurement." Using combinations of many electrical components and forming complex circuits, analog electronics allowed using their achievements to compile simple digital electrical appliances. Today, analog electronics is the basis for the circuitry of sophisticated modern electrical appliances.
One of the devices of analog electronics -The operational amplifier, which is a complex multi-stage circuit using semiconductors. In integral form, this device has two inputs that invert each other. It is noteworthy that one of the properties of the inverse signal receiving unit is a large value of the gain.
Integral execution implies thatThe operational amplifier is located in one of the working units of the microchip. In circuit design this device, like all other elements, received a special designation. As a rule, in operational diagrams, the operational amplifier is designated as a large triangle. However, recently you can find an alternative symbol for the amplifier - a rectangle with a small triangle inside. Most likely, such a designation is introduced to simplify the image of the device in the structural diagrams.
The use of operational amplifiers is veryvarious. These multi-stage instruments are used in a wide variety of amplifiers for various signals. In addition, the operational amplifier is often used in generators of electrical signals, as well as in frequency filters for the sound range. In addition, the amplifier has become an indispensable device in the schemes of control systems of many physical quantities (in particular, at weather stations).
The operating principle of an operational amplifier is oftencompare with pharmacy weights, the arrow of which deviates to the side where the load on the calyx is greatest. Only for the operational amplifier one needs to mark one of the cups with the sign "+", the second - "-", and replace the measured value with volts instead of grams. So, the amplifier compares the voltage module at one and the second input. If the potential difference on the direct input is greater than on the inverse, then the output forms a positive voltage (otherwise negative voltage).
Returning to the designation of operational amplifierson the principle of electrical circuits, it is worth noting that the direct input is often denoted by the sign "+", and the inverse - "-". However, such symbols are not always used! Sometimes on schemes the signs at the inputs are not set, but instead the inverse input is marked in the form of a small circle.
In order to reduce the sensitivityoperational amplifier to the technical fluctuations of the input electrical signal, the OOS is introduced into the operational amplifier - negative feedback. Due to the use of such a circuit component as an output connection with an inverse input through a special resistor, minor deviations from the specified input signal are not taken into account by the operational amplifier in operation.
Sometimes for operation of an operational amplifier inIn principle, the electrical circuits of complex devices use positive feedback, which connects the positive input and output through a dedicated resistor. When using positive feedback, an interesting side effect appears - the "hysteresis loop".
In conclusion, we note that operational amplifiers are used for both unipolar and bipolar power supplies.
