mains operated led night lamp


Posted on Feb 7, 2014

Here is a simple and powerful LED based night lamp circuit that can be operated directly from the 230V mains supply. The are total 24 white LEDs used and the lamp produces an output of around 15W. The resistance R1 and capacitor C1 provides necessary current limiting. The circuit is sufficiently immune against voltage spikes and surges. I would str


mains operated led night lamp
Click here to download the full size of the above Circuit.

ongly recommend that you rectify the mains power and use a filter capacitor, the flicker when powering an LED array like that is quiet intolerable to most people. Most LED lamps I built, have not a capacitor but a resistive voltage divider, for more long term reliability and reducing the chance of the LED`s to fail, when the capacitor has a bad day at switch on and overload the 1k resistor. If there is high contrast, both between the light and its surroundings, and between the on and off phases of the light, it is quite easy to see 100 Hz flicker I move my eyes past the light. The off period is more important than the frequency. Lights lit from UK mains at 100 Hz usually have off periods of about 5 ms and aren`t as bad as the tail lights of some cars that are 1 ms on and 9 ms off. I can see that they are flashing at any distance from about 5 metres to a couple of km. Some car tail lights are now lit at about 400 Hz, which is still visible but isn`t nearly as distracting. I haven`t had a chance to get a `scope on one of them to measure for sure. Also, it doesn`t really matter that only a few percent people find 100 / 120 Hz lighting intolerable, you shouldn`t be subjecting them to lighting like that, any more than you should put door lintels 1. 8m off the ground and only 5% of visitors knock themselves out. Scotopic vision is more sensitive to flicker than photopic vision so you`ll notice flicker more under low light...




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