7400 competition entry: 7400 Dimmer

Control your lights via a 7400 based dimmer. This is RodLophus’ entry for the open 7400 Logic Competition:

The idea is: For a typical dimmer, when you apply a pulse on the gate terminal of the TRIAC, it turns on – and stays on until the mains voltage crosses the 0V.┬áSo, varying the “firing angle” (“where” on the mains sinusoidal voltage the pulse will be applied) we can vary the amount of power that is delivered to the load.┬áThus, if the load is a lamp, its brightness will vary according to the TRIACs “firing angle”; the earlier we fire the TRIAC after the mains voltage crosses 0V (lower firing angle), the brighter the lamp will be.

Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.

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3 Comments

  1. “Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.”

    I thought the deadline has NOT been extended?

    1. it wasn’t, these were all entered on time, we just had them back-logged as we only posted one entry a day during the competition. There are 10-15 more, that will be processed today, and posted on the blog over the weekend, Perhaps some on monday as well.

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