Amplifier Circuit

This Multidirectional microphone amplifier circuit is often used in a panel discussion or a meeting room to capture the audio from all the partners without the need to give each microphone. Placing this in the middle of the table captures audio from each through which is formed by four electret capsules with a level control for each individual reception.

This two-channel amplifier provides power to 20 watts RMS from two line inputs. Ideal for use in computers since its price / performance / complexity is optimal.

In the 20 watt stereo amplifier circuit observed only one stage of the system because the circuit stereo, second channel are identical. The figures in parentheses are equivalent to the terminal for second channel. The core of this project is the integrated circuits from National Semiconductor, the LM1876, which provides two power operational amplifier with mute and standby function.

This 100W bridge amplifier circuit can increase the power level of the audio signal from a source that has a LINE output type.

The heart of this bridge mode amplifier circuit is the TDA7294 integrated circuit which is actually a power operational amplifier with a pre-amplifier circuit, temperature control and output short circuit protection. In addition the IC is equipped with separate input Mute (Mute output) and the STBY or Stand-By (Disconnect the power amplifier). Each IC amplifies half-cycle signal input and provides output 50W each.

The following circuit is a power amplifier for FM stations, this time with a power output of 70 watts.

The heart of this stage is an RF transistor (the BLY90) which, together with the classical passive components in such systems, performs the function of amplifying the radio signal present at its base to deliver to its collector.