A Solution to Improve the Quality of BJT Amplifiers

Anh Dang Thi Ngoc

BJT amplifier, Operational amplifier, multisim

A advantagae of BJT amplifier is wide bandwidth. However, when designing a amplifier has two disadvantages. The first, by given gain, the designing depends on many parameters (ex working area, value of resistors..) so it is dificult to meet with the application having changeable amplification. Secondly, the input resistance of them is small so the gain is not high if the source has a large internal resistance. To overcome the above disadvantages, the author proposed a amplifier designing using combination operational amplifier (OA) and BJT. The results on multisim simulation software also show that the amplifier has better frequency response.