KIS-3R33S

A simple, low cost, conversion of incandescent-lamp illuminator to a power LED By Dushan Grujich, on October 15th. 2012 My LOMO Biolam 70 has come with the OI-32 illuminator using a 220V AC 15W incandescent-lamp, which, when used for longer period gets very hot to the touch. This situation had me thinking of replacing incandescent-lamp with a power LED. My experimenting with power LEDs resulted in permanent conversion of the OI-32 illuminator. To drive the power LED I have used a low cost 10 W DC-DC Step Down Converter, KIS-3R33S module, capable of delivering up to 3A continuously. This module comes with output voltage preset to 3.3V. However, it is easy to readjust and have output set at any voltage from 1.21 V – 10.43 V, if the circuit is modified then the output voltage can be varied up to 20V. The final choice was 1W “Pure White” 150 lm LED with colour temperature of 6000º K, replacing 15 W lamp rated 90 lm at 230 VAC, which burns out too often due to excessive heat. Fig. 1 - Completed conversion with illuminator in use Different LEDs from different manufacturers operate at different maximum continuous voltage, which in turn determines the maximum current flowing through the LED. To protect LED and to provide stable light characteristics it is necessary to limit the voltage output from the KIS-3R33S module according to the specific requirements for each type of power LED, as specified by the manufacturer. For power LEDs, which I have used, manufacturer has specified maxi...