Description A adapter module for ESP 01 Wi Fi module 3 3V voltage regulator circuit and onboard level conversion circuit can make 5V microcontroller easy to use with ESP 01 Wi Fi module Also the item can be used withUNO R3 or compatible board Here is schenmatic http img banggood com file products 20160408023336ESP 01 20Adapter 20module 20Schenmatic pdf Features Working voltage 4 5 5 5V On board 3 3V LDO Regulator Working current 0 240mAInterface logic voltage 3 3V 5V compatible On board level shift circuit Note The item can be used with item 947259 item 947259 is not included Package included 1 x ESP 01 Adapter module