No, since "earth" and "ground" are synonymous for AC (power) systems and, historically now, as "plastic" underground piping is used for water supplies, earth was (and often still is for other reasons) also tied to the copper piping of the interior household "water fittings". W.r.t. completes the circuit thagrol (and others) is(are) referring to a common reference point which "0V" to which positive (5V, 12V ..) or negative (-12V) low-voltage DC supplies are referenced to. Where A.C. signals exist and screened cables are used that's where screen of said cable would be connected. The latter gets "more interesting" at higher frequencies when double-screening may be needed and when you get to high-voltages and/or high power RF transmitters or lightning protection well ... I've had the "pleasure" of working with pulsed TEA lasers using (pulsed) power supplies of ~200KV peak and integrating 5V TTL to 500V trigger/firing circuits to them - "fun and games" to screen/avoid false triggersSo we have three wires in our electrical outlets. One is + (they call it phase here) which is the live wire. The other one is - (they call it neutral here) which is the one that completes the circuit. And the third one is the earth (ground) wire. In your explanation, you say ground completes the circuit. Then what is the wire that we call ground here? Did we misname it?Going back to the original question, and assuming it's about the sort of low voltage circuits you'd interface to a Pi or Pico:
The ground wire serves two purposes:
- Completes the circuit. No ground means no return path for the current. An LED with a connection only to its +ve pin won't light.
- Provides a common level for 0 volts. Without that it's uncertain that a high on one board will be seen as a high on the other.
Trev.
Statistics: Posted by FTrevorGowen — Thu Mar 21, 2024 12:46 pm