Friday 7

Build a Candle Snuffer Using a 555 Timer

A couple days ago I posted an update on the Watkins-Johnson databook page that had an unauthorized gag graph titled, "WJ-G1/SMG1 Phase vs. VCTL vs. Frequency vs. Phase of the Moon." When RF Cafe visitor and sometimes contributor Dr. Marek Klemes* read that, he sent me a note about remembering this "Delayed Light Turn-Off" circuit from the Signetics 555/556 Timer Databook. It took a bit of creative Googling, but he managed to find the datasheet (to the right). The text was a bit washed out from the original low resolution scan, so I reproduced the labels (green). This Rube Goldberg-ish contraption works thusly: After a delay determined by the values selected for R₁ and C₁, the output of the NE555 timer goes high and causes resistor R_L to heat up enough to ignite match M₁. M₁ subsequently lights the fuse on firecracker FC₁, which has tied to its body a string that wraps around a pulley and holds a rock (which weighs precisely 2π pounds ...

RF Field Engineer Needed by PierCon Solutions

PierCon Solutions is a solid, tenured, and proven wireless consulting and engineering firm based in Lincoln Park, NJ. PierCon is a recognized leader in the wireless designs of in-building coverage, broadband, WiMAX/LTE, microwave, cellular, public safety, PCS, iDEN, and WiFi. As a provider of world-class engineering and consulting services our team of dedicated RF Engineers is seeking additional talent to help us continue our path to success. This RF Field Engineer position acts as the Site Engineer and Site Inspector for a large scale Public Safety communications Project located in Harriman, NY. The Field Engineer will perform daily surveillance and inspections of contractors / sub-contractors in accordance with contract specifications ...

A Brief Tutorial on Microstrip Antennas

Kenneth Puglia has a good article in Microwaves & RF magazine titled, "A Brief Tutorial on Microstrip Antennas - Part 1" (here is Part 2). Says Mr. Puglia, "This article, the first of a multi-part series on microstrip antennas