The power amplifiers use the voltage as well as the current to give high performance in getting the amplified signal of the main signal in the device and there the voltage and as well as the current is considered into the account for better working of the device.

In case of voltage amplifiers the amplifiers only use the voltage of the amplifier to get the maximum in case of this amplifier and here we every time use the voltage level of the amplifier to get the amplified signal that we always need. So here the amplifiers are transforming the current value into the voltage level value for higher impedance value.

In case of current amplifiers the amplifier uses the current to boost up the amplifier circuit to get the amplified signal of the main message analogue signal and there we will always find the maximum output of the device that has gone through proper amplification.

To know about these amplifiers and how they work we have to know about some of their characteristics that define their work in the applications. The things are the impedance that is to be measured as here we will always find in any type of circuit that uses the impedance as the resistance in the circuit.

There are also called something named reactance and the reactance is defined by the amplifiers maximum output delivered where it has to come over the amount of resistance stated in the circuit.

For voltage amplifiers we have earlier discussed that the device boosts up by the voltage applied and if here the voltage increase to a little value then the gain of the amplifier gets highly increased increasing the power of the main signal given as input in the amplifier device.

In the current amplifier the same thing is happening as here for a small change in value of the current the current gain get to a lot more and is estimated to be nearly about 100 and there lies the key to use the current amplifier.

In the power amplifier as the both current and the voltage is used to boost up the gain of the amplifier so it is much more efficient where the maximum output we can get out from the power increased from the amplifier. If there is a small increase in voltage then there will be a amount change in the current and the increased power will be more as here the power is the multiplication of the voltage with the current that makes a huge difference in the performance with the other amplifiers. So the power amplifier gives a maximum efficient output to the users. The multiplication of voltage value with the current value make a great change in the value of power and thus the gain of the amplifier get many more times greater than expected so here we get the maximum performance delivered. After much consideration power amplifiers are used a lot now.

Another type of amplifiers are there named operational amplifiers where the amplifiers act with some extent good with giving some feedback to the circuit and also to the users.

Some characteristics is to defined for the operation of the amplifiers. The one is the output impedance where the impedance is measured by the ohms unit and it only depends upon the resistance of the circuit.

Some feedback is also there where we will always get some output signal get fed back at the input of the device and here if we have a maximum amount of output signal fed back at the input then the response of the device gets higher creating maximum efficiency of the device.