Soldering 101

Intro to through-hole soldering
We will solder a blinking, customizable name tag. We will also discuss and explain the design and the theory of operation.

Circuit

 * A discrete astable BJT multivibrator feeding into a johnson decade counter, which drives the LEDs directly.
 * The counter can serve up to 10 segments.
 * The LED matrix can partitioned partitioned arbitrarily column-wise: multiple columns can be grouped onto a single counter output.
 * each counter output has one series current limiting resistor
 * last (unused) counter output feeds back to reset
 * multivibrator speed can be adjusted with a pot
 * on/off switch?

Components

 * LED, $0.04650 @ 1000: http://search.digikey.com/us/en/products/WP710A10SRD%2FD/754-1593-ND/2769819
 * CD74HC4017 decade counter, $0.4776 @ 50: http://search.digikey.com/us/en/products/CD74HC4017E/296-25989-5-ND/480317