## Duty Cycle Selector

Here is a unique project, duty cycle selector because duty cycle of pulse generated by this circuit can be varied from 10% to 90% in different 9 steps in the difference of 10%. The two complementary outputs and the sum of their duty cycle is always 100% make duty cycle selector more versatile.

### Circuit description of duty cycle selector

The duty cycle selector circuit only two low cost CMOS IC_{S} (CD4001 and 4017). The NAND gate N_{1} with N_{2} is configured as oscillator and generate frequency (ten times of output frequency) is given to pin 14 of IC_{2}. IC_{2} divides the input frequency by a factor of 10. The output frequency is determined by oscillator and be in range between 0.1 Hz to 50 KHz.

The value of generated frequency is determined by the formula

**F = 1/2.2R _{2}C_{1}.**

This formula is only verified when R_{1} = R_{2} and the value of R_{1} is not less than 10 KΩ

### PARTS LIST

#### Resistors (all ¼-watt, ± 5% Carbon)

R_{1} = R_{2} > 10KΩ

C_{1} = Determined by output frequency

#### Semiconductors

IC_{1} = CD4001

IC_{2} = CD4017

#### Miscellaneous

SW_{1} = 9-way rotary switch