Diode, BJT and MOSFET states of operation, DTL, RTL and TTL gates, fan out, noise immunity and effect of capacitive load. ECL and PMOS, NMOS and CMOS gates. TTL- CMOS interfacing circuits. Sweep circuit techniques. Bistable, monostable and astable mulivibrators circuit analysis and design using discrete component. A 555 timer and its applications in timing circuits. Sampling theory ,analog to digital and digital to analog converters.