|In most cases,
when measuring DC voltages in an electronic circuit, the black negative
lead is clipped to the negative connection of the battery or supply.
This leaves one hand free.
The red lead is then used to measure the various voltages in the circuit.
These voltages are therefore measured WITH RESPECT TO negative.
|wrt = with respect
In the diagram,
point A is 18 volts positive wrt to D. (this is actually the battery voltage).
A is +12 wrt
C and +6 wrt B.
B is +6 wrt C
and +12 wrt D.
Looking at the
Copyright Graham Knott 1999