Week #6: Special Purpose Diodes & Resistor Codes & Series

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rjagodowski
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Joined: Fri Sep 04, 2015 6:59 pm

Week #6: Special Purpose Diodes & Resistor Codes & Series

Post by rjagodowski »

PLEASE NOTE: Monday, 10/12, is Columbus Day and there are no classes at STCC on that day. Tuesday, 10/13, will follow a Monday schedule, so all Monday classes will meet on Tuesday. Tuesday classes are cancelled for the week. Those of you in the Tuesday lab section WILL NOT have EET-200L lab on Tuesday this week. Thursday morning labs WILL meet as usual.)

We'll discuss various Special Purpose Diodes. Emphasis will be on the Schottky, Tunnel, LEDs & Laser Diodes, Photodiodes, and varactor diodes.

We'll also spend a bit of time discussing Resistor Codes & Series. The standard resistor color code (which I am SURE you ALL have memorized!!!) is one way of defining a resistor's nominal value, but doesn't work well for small, surface mount components. We'll look at the standard color code and other methods in use. By the way, the traditional color code used on resistors is because back in the early days of electronics, BEFORE printed circuit boards, components were mounted between connection points on various terminal strips. By painting bands around the circumference of the component, then it's value could be read from any angle, regardless of how the component was mounted during assembly. Here's a picture of a 1948 Motorola TV set showing it's construction:
1948_Motorola_Goldenview_Chassis.jpg
1948_Motorola_Goldenview_Chassis.jpg (1.31 MiB) Viewed 1347 times

Modern surface mount components are so small, that colors wouldn't be a viable option. Fortunately with modern printing technology, component values are often written on the component using other methods such the 3-digit code and the EIA-96 code.
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