DIGITAL REGULATOR CIRCUIT DIAGRAM

1.25V-15.19V Regulator/Adaptor Variabel Digital, is a series regulator with variable output from the digital 1.25V to 15.19V The first section of the circuit comprises a digital up-down counter built around IC1, a quad 2-input NAND Schmitt trigger (IC CD4093), followed by IC2, a binary up-down counter (CD4029 IC). Two gates of IC CD4093 are used to generate the up-down logic using the push buttons S1 and S2, respectively, while the other two gates form an oscillator to provide clock pulses to IC2 (CD4029). The frequency of oscillations can be varied by changing the value of capacitor C1 or preset VR1. IC2 receives clock pulses from the oscillator and produces a binary sequential output. As long as its pin 5 is low, the counter continues to count at the rising edge of each clock pulse, but stops counting as soon as its pin 5 is brought to logic 1. Logic 1 at pin 10 makes the counter to count upwards, while logic 0 makes it count downwards. Therefore the counter counts up by closing switch S1 and counts down by closing switch S2. The output of counter IC2 is used to realize a Digitally variable resistor.