On 1/2/2012 8:23 PM, Richard Fjeld wrote: > It is simply a 12V incandescent bulb. Apparently the small metal box in-line > on the power cord is a switching PS instead of a step-down transformer.
YES. This is a VERY common noise source, and finding a step-down transformer for products like this can be quite difficult. The problem is that while 12VAC will run the device just fine, the available mounting space is just large enough for a switching power supply, and far too small for a transformer. If you go to an electrical supply store to buy one, they will sell you an unmarked box with wires coming out that they call an "electronic transformer." What's inside is a very noisy switching power supply. MAYBE it will have a UL label, indicating safety agency compliance. and MAYBE that will be real, but UL standards say NOTHING about EMC. I'm told that it is possible to buy clean power supplies for low voltage lighting, but I've never managed to do so. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
