116 of over 1,000 results for "3 volt dc transformer" Amazon's Choice for 3 volt dc transformer SMAKNÂ Premium External Power Supply 3v 1A AC/DC Adapter, Plug Tip 55mm x 25mm 44 out of 5 stars 1,678 $599 $ 5 99 Get it as soon as Fri, Oct 15 FREE Shipping on orders over $25 shipped by Amazon 3V 1Amp Power Adapter Supply AC to DC 3Volt 1000mA 21mm X Mentor 60,309 10,606 Sudha Sarita said Using a step down transformer 12 V can be cut down to 15 V In a step down transformer number of turns in secondary windings is less than the number of turns in primary windings That only works for AC The OP seems to be asking mainly about DC power Primary 240 volt , secondary 12 volt Ratio = 240 over 12 = to 1 So Vp/Vs = ( which is also the turns ration of the transformer ) Hence current ratio Ip over Is = 1 to Ip/Is = 1/ Secondary load current 6 amps Primary current = 6 * 1/ = 03 amps Check 03 * 240 = 72 = 6 * 12 This is true only for inductive wound transformers When dealing with "electronic"
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