8-bit shift registers (expand output) - 74HC595
ATMega328 32K microcontroller with pre-loaded Arduino Uno bootloader
This is a common 555 timer/oscillator from TI. A classic for all of those first year circuits projects where you need to blink an LED, generate tone, and thousands of other great beginning projects. Google around for a huge list of resources and example projects.
8 Darlington Arrays in 18-Pin DIP Package part # ULN2803A. Perfect for running relays and high-power devices up to 500mA and up to 50V! Resources: Nuts and Volts article on Driving High Current Loads
Potentiometers are incredibly useful, whether you're controlling the volume on your stereo or the 'mood lighting' in your room. The problem with traditional potentiometers the fact that your microcontroller doesn't have an easy way to interface with them. Digital Potentiometers solve that problem by allowing you to control a voltage splitter with digital...
This chip will add 8 channels of 10-bit analog input to your microcontroller or PI It's super easy to use, only 4 pins are required.
2 Wire Serial Communication (I2C) EEPROM - The back bone of any microprocessor project. These 8 pin chips need only two wires to communicate and retain their data even with power failure. Use the 256K EEPROM for some serious data storage!
These are very common, high quality NPN transistors
If you've ever wondered how to control the headlight of a car from a microcontroller, a MOSFET is what you need.
Atmel's itty-bitty ATtiny85 8-Bit Processor. 8K of program space, 6 I/O lines, and 4-channel 10 bit ADC. Runs up to 20MHz with external crystal. Package can be programmed in circuit.
Basic 7805 voltage regulators in the TO-220 package. A must have for basic 5V electronics.
This 24-DIP IC has 6 built in 10K OHM potentiomters which can be controlled using the Arduino's built in SPI interface.
This is the basic L7812 voltage regulator, a three-terminal positive regulator with a 12V fixed output voltage.
This is the basic LD1117V33 voltage regulator, a low drop positive regulator with a 3.3V fixed output voltage.
The seven band graphic equalizer IC is a CMOS chip that divides the audio spectrum into seven bands. 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz. The seven frequencies are peak detected and multiplexed to the output to provide a DC representation of the amplitude of each band.