Electronic Circuits and Diagram-Electronics Projects and Design

Digital Volume Control Circuit Description This is the circuit diagram of a digital volume controller for any sort of audio amplifiers or almost any circuit where a mechanical potentiometer is there(conditions apply). Simple and low cost, the heart of the circuit is DS 1669 digital potentiometer IC from Dallas Semiconductors.The circuit has no external components other than two pushbutton switches and a capacitor. Tips S 1 increases the volume & S2 decreases. The input audio signal must be not less than -0.2 Volts. If some clipping problem occurs, use a dual power supply of +5 & -5V.( Not shown in…

Tone Generator Circuit Description Here we present a simple and low cost tone generator circuit, a ding dong bell suitable for calling bell purposes.It is made around IC 8021. It is an 8 pin IC but only four pins are shown here. 8021 has an in-built circuitry to produce ding dong sound each time its pin 3 is pulled low. The sound is stored in a 4 bit ROM. A complementary-pair, two-transistor amplifier is used to amplify the sound to a fair level of audibility. A piezoelectric tweeter or an 8-ohm, 500mW speaker  can be used at the output. Each…

Make a Digital Stop Watch Description A digital stop watch built around timer IC LM555 and 4-digit counter IC MM74C926  with multiplexed 7-segment LED display. MM74C926 consists of a 4-digit counter, an internal output latch, npn output sourcing drivers for common cathode, 7-segment display and an internal multiplexing circuitry with four multiplexing outputs. The counter advances on negative edge of the clock. The clock is generated by timer IC LM555. The circuit works off a 5V power supply. It can be easily assembled on a general-purpose PCB. Enclose the circuit in a metal box with provisions for four 7-segment displays,…