This week Bob shows you the well known utility timer chip, the 555. He demonstrates both the Monostable and Astable modes as well some additional options.
Link to Wikipedia page:http://en.wikipedia.org/wiki/555_timer_IC
Page includes the graphics used in the show, and a good description of how how the IC can be used.
IC (including supplier) used: http://www.mouser.com/Search/ProductDetail.aspx?qs=gb35HGp1gQKvnuQa7j7RAQ==
and the datasheet: http://www.ti.com/lit/ds/slfs022h/slfs022h.pdf
470uF Capacitor with different resistors
A 2.2kΩ resistor, yields a 1 second time.
A 10kΩ resistor, yields a 6 second time.
A 47kΩ resistor, yields a 25 second time.
A 10kΩ pull-up resistor was used on the push button.
Favorite calculator: http://clarkson-uk.com/555-timer/operation/frames2.html
On the breadboard, 4.7uF and 100uF capacitors, along with R1 resistors of 470Ω and 4.6kΩ were used. In all examples, R2 is a 4.6kΩ resistor.
R1 Cap Freq. Duty Cycle
4.6kΩ 4.7uF 22Hz 66%
4.6kΩ 100uF 1Hz 66%
470Ω 4.7uF 32Hz 52%
470Ω 100uF 1.5Hz 52%
Favorite calculator: http://www.ohmslawcalculator.com/555_astable.php