| The 4 bit D to A converter
consists of four resistors, whose values are in the ratios shown in the
left hand diagram above.
They can go high or low, as shown in the right diagram. |
| The voltage out is determined
by which of A B C D are high and which are low.
The resistors are usually not "hard wired" high or low as shown, but taken high or low by signal voltages. |
| The digital signals at A
B C D can be between 0000 and 1111, which gives 16 steps, suitable for
a volume control etc.
If finer resolution is required, then 8 bits can give 256 steps. |
Copyright Graham Knott 1999