Assuming that your transformer is stepping down to a reasonable voltage, here is a guess. When your potentiometer wiper is near the lower end, the resistance seen by the transformer will be very low, and the current will be very high, causing sparks and overheating.simulate this circuit - Schematic created using CircuitLab.

1. where to find Three Function-E27 Super Motion Sensor Led Bulb?

Hello, Super motion sensor light is very convenient for home using. Especially the LED motion sensor. You are lucky, the Synron Group is the wholesale of LED sensot motion lights, there also many household induction light

2. Using 220V LED bulb in US on 120 VAC help?

Sorry, you would need a transformer, not an adapter. I know it's not the answer you want

3. Second LED bulb in each fixture burns out, what should I replace?

Older dimmer switches are not necessarily compatible with "dimmable" LED lamps. Replace the dimmers with those designed for LED's, or replace with a standard wall switch, and use remotely-controlled lamps.BTW, there is no problem disposing of "dead" LED lamps -- most should comply with RoHS and contain little or no hazardous material. While the emitters may contain tiny amounts of arsenides, they are well sealed in plastic. Perhaps you are confusing LED's with fluorescent lamps, which have small amounts of metallic mercury

4. How much current does a 22-watt LED bulb take?

Use the formula 22W/ Voltage (V). For 240 volts supply current will be 92 mA .Hold on !!! LED is a current decided andbconstant voltage device. Hence an appropriate controller must be some sort of SMPS , ensuring constant operating current when supply itself varies. Hence you to accommodate variation in V while calculating I . Silver line is - who pays for this extra and you just have rectified AC to the LED chain !

5. Can I use an LED bulb in a 3-Way fixture?

HEHE I made my own 3 way LED. I had a popped CFL and carefully removed the curleycues to get the base. I then put in two LED drivers (from 120VAC) and two LEDs which were 5 watt and 2 watt. I think luxeon stars. It works, albeit not as good as I would like. The LED drivers are tiny and did fit into the CFL power supply base

6. Is it safe to use a 40-Watt LED bulb in a low-beam headlight that came originally with 55-Watt halogens?

forget about that kit !! you need something that is (1) legal to use in the State you live in and (2) will properly fit that vehicle

7. A 1USD 11W led bulb circuit and parts analysis

Apparently, the heat problem will be more in countries using 117/120 volts than in those where the domestic supply lines run on 220/230 volts, for a given wattage

8. Is it safe to use a 28W LED bulb in a MAX 15W lamp fixture?

It really would be helpful if you would provide more information, especially the specifics on the light bulb.But - assuming the bulb draws 28 watts (and it is not the equivalent to a 28 watt incandescent light) then no, this would not be safe

9. LEDinside: LED Bulb Prices Rebound in China in April as Low Quality Products Exit Market-Industry News-Zhongshan City Luck Shine Lighting Technology Co., Ltd

Global 40W replacement LED bulbs Average Sales Price (ASP) dropped 1.0% in April 2015 to US $11.8, according to LEDinside's latest LED bulb retail price survey. Global prices for 60W equiv. LED bulbs slightly decreased 0.1% to US $15.9. Price declines was most evident in Europe and North America region, especially in UK. In contrast, LED bulb prices in Asia has rebounded, this was most markedly observed in the Chinese market where low priced and poor quality products have gradually exited the market, leading to the brief price uptick. In the UK market, 40W equiv. LED bulb prices further declined 4.6% in April, after a 4.7% price drop in March. Lighting products that have underwent earlier price upticks all dipped. For instance Osram's 6W 470 lm LED bulb prices declined 35% to US $8.07, while Auraglow 7W 480 lm LED bulb prices plunged 30% to US $6.2. Other LED bulb prices that have plummeted in the UK, include Toshiba 7.5W 470lm LED bulbs and Philips 6W 470 lm LED bulbs. In Germany, 40W equiv. LED bulbs have continued its steady price decline since 4Q14, but price falls gradually eased. In April, LED bulb prices were down 2.1%, while Samsung, Toshiba, Osram and other renowned LED brands have further lowered retail prices. In Asia, 40W equiv. LED bulb prices dropped 5.9% in Taiwan, since certain manufacturers sales promo have dragged down overall market retail prices, for instance Neo-Neon Holdings LED bulb prices tumbled more than 50% to US $3.04. In China, LED bulb prices climbed up 4.1%, marking the first price surge in 2015 as certain low-priced products exited the market. In addition, certain product prices increased for example Pak Corporation's 5W 500 lumen LED bulb prices increased 6.55% to US $2.47. Other market regions price fluctuations remained small, currency exchange fluctuations has been the main reason. As for 60W equiv. LED bulbs, prices dropped 6% in April and was the region where prices fell the most. A large number of LED bulbs ASP decreased, with only a small portion of LED bulb prices plummeting. For instance, Philips 9.5W 860lm LED bulb prices dropped 38% to US $6.2, while Osram's 10W 806 lm LED bulb prices declined 25% to US $11.18. Prices in Germany also slid 2.6%, resulting in smaller price fluctuations. LED bulb prices in U.S. also slid 2.8%, with certain product price fluctuations much larger than others including Philips and Osram brands. In China, LED prices rose 1.1% as low priced products were withdrawn from the market, leading to the price uptick. Market prices in other regions remained relatively stable. Chinese manufacturers tend to use low-pricing strategies to acquire market share, hence it is difficult to ensure product quality. Industry developments has led to the gradual abandonment of low priced and bad quality products. Market restructures are also spurring small manufacturers to withdraw from the market, but from a long term perspective short term price declines is just the current market response to market demands. Prices have continued to plunge, but the cause of declines will eventually shift from market competition to technology.