I ordered some cheap Volt\Amp meters from Banggood and also a DC-DC buck-boost LTC3780 converter board. Many people have made YouTube videos and written Instructables about how to make a variable PSU from this combination (plus a DC source such as 12V from an ATX power supply) but nearly all of them are WRONG - but the solution is simple!
Note: This type of VA meter has thick Black+Red wire and thin Black+Red+Yellow wires. Do not confuse it with the other types which may have a thick blue wire or a thick yellow wire!
Many people who have built a power supply using these two modules have complained that the over-current pot on the Buck\Boost board did not seem to work. Other people have complained that the Ammeter reading was incorrect. A few have blown up their boards.
The diagram below shows the typical wiring arrangement that is used by most of these designs, but I have added in some extra purple lines to indicate the 0V traces which are already inside the DC-DC Buck\Boost board and already inside the VA meter.
Usually described as "LTC3780 Automatic lifting pressure constant voltage step up step down 10A 130W" |
Digital VA meter (note they seem to only have one decimal place for voltage, not two as shown in this stock picture!) |
Note: This type of VA meter has thick Black+Red wire and thin Black+Red+Yellow wires. Do not confuse it with the other types which may have a thick blue wire or a thick yellow wire!
Many people who have built a power supply using these two modules have complained that the over-current pot on the Buck\Boost board did not seem to work. Other people have complained that the Ammeter reading was incorrect. A few have blown up their boards.
The diagram below shows the typical wiring arrangement that is used by most of these designs, but I have added in some extra purple lines to indicate the 0V traces which are already inside the DC-DC Buck\Boost board and already inside the VA meter.