![]() ![]() But they are susceptible to damage from short disturbances on the incoming voltage CS protects DS from these disturbances - see later for component details for CS. Schottky diodes are like normal diodes but they have a much lower forward voltage, so they don't waste much power, and they don't heat up as much as normal diodes do. The input current then passes through DS, which is a Schottky diode, with CS connected straight across it. Just remove the fault and it will cool down and "reset". You could use a time delay or slow-blow fuse in these positions, but I've specified a device called a PTC resettable fuse, which has comparable performance but doesn't need to be replaced, for both positions. F2 should have a slightly lower rating than F1. Output current flows through F2 which protects the regulator against a shorted output. Input current flows through F1 which protects the source against a fault in the regulator circuit. If you have no idea how much current your appliance(s) need, you could assume 5A for I L.į1 and F2 - PTC resettable fuses for input and output I L is the maximum current, in amps, that you will be drawing from the output of the regulator. In this description I will be mentioning I L a lot. The other dotted box represents the part you will need to build - a circuit board inside a plastic enclosure, with holes drilled for ventilation (or you could mount the heatsink on the outside). This will minimise unnecessary voltage drop and power dissipation (heating) in the regulator. I've shown this with an arrow marked "UNSMOOTHED". ![]() The positive DC output is on the blue wire.Īny appliances that draw a lot of current and that don't need a clean DC supply should be powered from this point. I've shown the relevant parts of the internal circuit. ![]() Your existing Magnetek 6415 is on the left. I've explained them below, and provided lots of links to specific recommended components on the Digikey web site. Many of the component values aren't specified on the diagram because they depend on your requirements. I intend to use this as a reference post that I can use to answer future similar questions. Don't be freaked out by the amount of detail here. "NOTE: These converters are not suitable for battery charging." When 120 VAC is again available, connect it to RV and put manual switch back in "CONV" position for Power Converter section to supply 12 VDC power for RV." This will automatically switch 12 volt lights and motors to RV battery for power. "When 120 VAC is NOT connected to the Electrical Center via commercial power or AC generator, put MANUAL SWITCH in "BATT" position. "Equipment limited to operation from pure 12 volt battery power including 12 volt TVs, radios, stereos, unfiltered fluorescent lights - must be connected directly into RV storage battery line, or equipped with filter - as Converters do not produce the "pure" 12 volt DC needed by these items." "Provides 12 volt DC power - up to load limit - to operate 12 volt lights and motors in RV when connected to 120 volt power source." There is a connection for a battery but it goes into a selector switch so the loads that are powered from the "converter" can be switched over to the battery when there is no mains power. I can draw up a circuit diagram and choose the components if you tell me how much current you need to draw from the regulated and smoothed 12V rail.Īccording to the manual (also linked in the first post) it is not a float charger. This requires a circuit consisting of about ten components, which you can build up on a piece of stripboard. Your best option for powering devices that need clean DC is a low dropout (LDO) regulator, powered from a large smoothing capacitor that's fed from your "converter" via a diode. If you are only loading it lightly, and/or if one or more of your loads includes a large capacitor that "smooths out" the voltage in between the camel humps, the voltage you measure on your multimeter will be higher than the specified 12V. The characteristics of the output voltage will depend on what it's connected to. The output voltage consists of a line of camels' humps, not a flat DC voltage, as shown on the right in this picture.Īs the manual says, "equipment limited to operation from pure 12 volt battery power including 12 volt TVs, radios, stereos, unfiltered fluorescent lights - must be connected directly into RV storage battery line, or equipped with filter - as Converters do not produce the "pure" 12 volt DC needed by these items." It's "DC, Captain, but not as we know it". That "converter" is a full-wave rectified power supply without smoothing. Hi there and welcome to Electronics Point ![]()
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