Where is the best place to place the 50HZ trap?

l印度阿三n

Where is the best place to place the 50HZ trap? [Copy link]

I made a 1000x amplifier and found that the 50Hz interference is very serious. So I wanted to use a notch filter to filter out the 50HZ interference. Now, the question is, where should I put the notch filter? Should I put it at the front end of the amplifier or at the output part? Please share your experience~

仙猫

It may be better to divide the amplifier into two sections, not to amplify 1000 times at once, and insert the notch filter between the two amplifiers. The reasons are: 1. It cannot be placed at the end, because the 50Hz may saturate the amplifier when it is very strong, and once saturated, it will produce high-order harmonics, which are not easy to filter out. 2. It may not be suitable to put it at the front because the signal is too weak. How to distribute the gain of the two amplifiers depends on the nature of the signal and the S/N ratio. For reference only.

maychang

If the 50Hz interference is introduced from the power supply, you should consider avoiding the power supply interfering with your amplifier. First, you should determine where the interference is introduced.