DS1302 is a tickle-charge timekeeping chip which contains a real-time clock/calendar and 31 bytes of static RAM. DS1302 uses serial communication to interact with microcontrollers. Also, it automatically adjust the date for the month with fewer days. Clock operates in 24hr or 12hr format with an AM/PM indicator. DS1302 chip is also commonly used as DS1302 RTC module which comes with a 32 kHz crystal and on-board battery backup all in a small SIP module that is compatible with a breadboard. DS1302 module are used by makers with Arduino, Raspberry Pi and other Micro-controllers.

The uA723 is a precision integrated-circuit voltage regulator, featuring high ripple rejection, excellent input and load regulation, excellent temperature stability, and low standby current. The circuit consists of a temperature-compensated reference-voltage amplifier, an error amplifier, a 150-mA output transistor, and an adjustable-output current limiter.The uA723 is characterized for operation from 0C to 70C.

4N35 optocoupler consists of gallium arsenide infrared LED and a silicon NPN phototransistor.Isolation test voltage 5000 VRMS. Input-output coupling capacitance < 0.5 pF . 4N35 optocoupler consists of gallium arsenide infrared LED and a silicon NPN phototransistor.Isolation test voltage 5000 VRMS. Input-output coupling capacitance < 0.5 pF . 4N35 optocoupler consists of gallium arsenide infrared LED and a silicon NPN phototransistor.Isolation test voltage 5000 VRMS. Input-output coupling capacitance < 0.5 pF .

LM386 is a widely used audio amplifier IC manufactured in 8 pin dip, VSSOP, SOIC and other packages. The IC is basically designed for low voltage commercial applications, apart from commercial applications it is also a famous IC among electronic hobbyists and experimenters. The internal gain of the IC is set to 20 but it can be adjusted by connecting a resistor and a capacitor in series between the pin number 1 and 8, by this procedure the user can adjust the gain between 20 to 200. Due to the small size, low quiescent current and low voltage requirements this IC is ideal to use in wide variety of portable battery operated applications and devices.

The ATMEGA328P-PU is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega328P-PU achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU),allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.

The ATmega328P-PU AVR is supported with a full suite of program and system development tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators, In-Circuit Emulators, and Evaluation kits.