Sawtooth Wave Generator Using 4-Bit DAC

The sawtooth wave generator circuit operates by combining timing, counting, and digital-to-analog conversion stages powered by a regulated 9V battery source. Energy from the battery is stepped down and stabilized to a steady 5V DC supply using the L7805 voltage regulator (IC1) along with decoupling capacitors like C1, C2, and C3 to filter out noise. The heart of the timing sequence is the NE555P timer IC (IC2), configured in an astable or clock-generating mode using resistors R1, R2 and capacitors C4, C5 to produce a continuous train of square-wave clock pulses. These clock pulses are fed directly into the 74LS93 4-bit binary counter IC (IC3). As the counter receives each clock pulse, its four output pins cycle sequentially through binary states from 0000 to 1111, resetting back to zero to repeat the cycle. This 4-bit digital output drives an R-2R resistor ladder network composed of precision resistors (R3 through R9), which converts the digital binary count into a corresponding staircase-like stepped voltage level. Finally, the LM358 operational amplifier (IC4) buffers and conditions this analog signal, utilizing feedback resistors R10 and R11 to set the desired gain and impedance characteristics before passing the final periodic sawtooth waveform out through connector J1.