Power circuits such as power amplifiers and voltage regulators pass significant currents. Under these conditions, the resistance of thin copper circuit board tracks can become important. To minimise this resistance, the connections to the 0 Volt line should be as close together as physically possible.
Failure to use single point earthing can have the following consequences ...
- Parasitic oscillations. The circuit oscillates unexpectedly. Both low and high frequency oscillations can occur.
- Mains Hum. 50/60 Hz AC mains supply hum can appear in the output. With audio systems this is a low pitched annoying humming noise. With DC supplies, the DC may not be as smooth as it could be.
