MOSFET is an electronic device having excellent switching characteristics, and is widely used in electronic switch circuits required, such as switching power supplies and motor drives, as well as lighting dimming. Relays are very familiar Another module has switching characteristics, but because the working principle of the relay is generally achieved by mechanical contact on and off purposes, which inevitably results in a very short time under the switch, the relay the situation does not work, another Baba sounds when the contact switch in some cases is more annoying thing.Use this module electronic building blocks with Ard uino 4 IRF540 MOSFET switches use the same, but changes to the way the original four. Use reference Ard uino 4-way switch IRF540 MOSFET modules:We designed this four MOSFET switch can provide up to 4 sets of electronic switches, were used to control the different circuit blocks. Affected MOSFET works, the electronic building blocks can be used to control the DC circuit, such as a DC LED screen, etc., are not suitable for controlling the AC circuit. The limit switch can be used to control the MOSFET 100V / 33A DC circuit, but control is not less than the minimum DC voltage proposal 9V.On the circuit connected at one end of the connection is slightly more controlled some trouble. 12V to control the LED lights, for example, first to the positive (+) and negative (-) connected between the power supply;Then take positive LED lights with the module connected to the positive (+) and negative LED lights with the connection to the switch 1 (S1);If there are other LED lights with the need to control, the same LED lights with only the positive cathode module is connected to the (+) and negative LED light strip is in turn connected to the switch 2 (S2), switch 3 (S3), the switch 4 (S4) on;Wire control terminal is much simpler, we only need a sensor cable, the corresponding control port and Ard uino sensor expansion board connected, you can control these by Ard uino 12V LED lights brought. Experiment, we picked up two LED lights.Test code is as follows:int s1Pin = 6;int s2Pin = 7;void setup () {  pinMode (s1Pin, OUTPUT);  pinMode (s2Pin, OUTPUT);}void loop () {  int i;   digitalWrite (s1Pin, HIGH);  digitalWrite (s2Pin, HIGH);  delay (500);  digitalWrite (s1Pin, LOW);  digitalWrite (s2Pin, LOW);  delay (500);   for (i = 0; i <10; i ++) {    digitalWrite (s1Pin, HIGH);    delay (500);    digitalWrite (s1Pin, LOW);    delay (500);  }   for (i = 0; i <100; i ++) {    digitalWrite (s2Pin, HIGH);    delay (50);    digitalWrite (s2Pin, LOW);    delay (50);  }}