1. The complement of sum of the variables is equal to the product of complement of variables.
2. The complement of product of the variables is equal to the sum of the complement of variables.

To verify this theorem let’s construct a truth table

1	2	3	4	5	6	7	8	9	10
0	0	0	1	1	1	1	0	1	1
0	1	1	0	1	0	0	0	1	1
1	0	1	0	0	1	0	0	1	1
1	1	1	0	0	0	0	1	0	0

If we compare column 4 and 7, they are identical proving first law stating

If we compare column 9 and 10, they are identical proving second law stating

Phase shift oscillator

An oscillator circuit which uses RC network as a combination of resistors and capacitors for its frequency selective parts is called RC oscillator. Phase shift oscillator is an electronic oscillator which has inverting amplifier and a feedback filter which shifts the phase of the amplifier output by 180 degree at the oscillation frequency.

• Oscillators converts DC signals into AC signal.
• Oscillator generates pulse type output along with square, saw-tooth and sine wave.