A Basic Transistor Amplifier with self-bias

This circuit will amplified the input signal with self-bias or feedback which can prevent amplitude distortion. However, it has two small drawbacks. It is only partially effective and, therefore, is only used where moderate changes in ambient temperature are expected.It reduces amplification since the signal on the collector also effects the base voltage. This is because the collector and base signals for this particular amplifier configuration are 180 degrees out of phase (opposite in polarity) and the part of the collector signal that is fed back to the base cancels some of the input signal. This process of returning a part of the output back to its input is known as DEGENERATION or NEGATIVE FEEDBACK. Sometimes degeneration is desired to prevent amplitude distortion (an output signal that fails to follow the input exactly) and self-bias may be used for this purpose.

Common Mode and Differential Mode Filters to limit EMI Issues

This EMI filter include common-mode filter and differential mode filter. Generally Differential mode filter filters noise less than 30MHz and Common mode filter filers noise from 30 MHz to 100 MHz. Both filter have an effect on the entire frequency where EMI needs limiting.