restifo

Member Since: January 11, 2012

Country: United States

  • I’ve had to deal with those regulations for shipping chemicals and equipment. Lest anyone think it’s just looking things up in a table, the rules are not always clear. Sometimes the rules read like some horribly written nested if-then-else statements; you’re down three to four levels and trying to keep things straight. Other times, what you’re shipping does not cleanly fall into any category; in that situation, you literally have to just pick a designation, follow the rules for it, and hope someone somewhere doesn’t come after you.

  • “I understand the ‘shake it all about’ part, but is this really what it’s all about?”

  • My dad, who was an EW in the Navy, taught me the conceptual idea of how a transistor works as a switch using a fork, a knife, and a spoon. Obtain a fork, knife and spoon. Make the knife the collector. Make the base the spoon. Make the fork the emitter. Lay them out just like a transistor symbol but don’t connect them.

    When no voltage is applied, current can’t “jump” from the knife to the fork. When you apply a voltage, you “nudge” the spoon in….current can now jump from the knife (collector) to fork (emitter). This is obviously for NPN. Remove the voltage, pull away the spoon. It also helps you remember whether you need a high or low voltage. You can reverse the concept and “pull” the spoon for a PNP. Think “nudge” (“n”) for NPN and “pull” (“p”) for PNP.

    I’ve found it an easy way to abstractly think about a transistor before learning about PN junctions/holes/electrons and such.

  • My dad, who was an EW in the Navy, taught me the conceptual idea of how a transistor works as a switch using a fork, a knife, and a spoon. Obtain a fork, knife and spoon. Make the knife the collector. Make the base the spoon. Make the fork the emitter. Lay them out just like a transistor symbol but don’t connect them.

    When no voltage is applied, current can’t “jump” from the knife to the fork. When you apply a voltage, you “nudge” the spoon in….current can now jump from the knife (collector) to fork (emitter). This is obviously for NPN. Remove the voltage, pull away the spoon. It also helps you remember whether you need a high or low voltage. You can reverse the concept and “pull” the spoon for a PNP. Think “nudge” (“n”) for NPN and “pull” (“p”) for PNP.

    I’ve found it an easy way to abstractly think about a transistor before learning about PN junctions/holes/electrons and such.

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