The resulting volume is the same as a 0.25W speaker; Audio interface: 3.5 , you can connect to the audio source of mobile phone, mp3, computer. (The computer audio interface is 3.5, the audio cable used is 3.5 to 3.5 audio cable, the mobile phone and MP3 interface are different, use the corresponding audio cable to 3.5) If you use other voltage or current that does not meet the requirements, the power supply or positive and negative Extremely reversed, there will be devices burned Some that the power supply is 24V, then the input 12V device will not be damaged. This understanding is wrong. The circuit eventually constitutes the oscillation circuit. If the voltage and current are not enough, the circuit will not oscillate, which will cause the triode to conduct directly to the ground, and the triode will burn out. First, the circuit parameters Power supply input voltage: 24V DC; Power supply current: 2A-3A; Power supply interface: positive and negative within 5.5-2.1; Audio interface: 3.5 audio port; Product size: length 8.5CM x width 8.5CM x height 20CM; Secondary coil size: diameter 4CM height 10CM Number of coil turns: 370 turns, the enameled wire with a coil diameter of 0.2, we are winding when the coil is shipped; The finished product weight is about 190 grams; Colour:Photo Color Material:Metal Package Contents: 1 x Music Coil Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.