Password Security Switch for electronics devices using only one mosfet

Hello everyone!! welcome in a new task , In this task we are going to make password security switch using only one mosfet for all electrical or electronics devices ,Basically the password security switches , devices and projects are develop by using arduino ,micro-controllers and IC ( integrated circuit ) but this one will be controlled by only one mosfet , its a interesting in this task

Here are the list of all components to make password security switch 

  • IRF540 MOSFET 
  • LED
  • 9 SWITCHES NO(normally open) TYPE
  • DIODE 1N4007 

STEP 1-  First we need zero pcb and there we have to install all the nine switches one by one , after installing properly solder all the pins of switches

STEP 2- Now time to choose password, you can choose any four or five switches for password ( suggested to use four switches to make four digit password ) we have used four switch it means five switch will be left. The five switches will be used for reset switch , connect all the switches in parallel

STEP 3- Now add capacitors, the number of capacitors will decide the digits of password if we want to make four digit password than we need only four capacitors , here we are using 10v/470uf capacitors

The capacitors positive will be connect to the series of four password switches ,After installing and soldering all the switches i am going to explain how the capacitor will perform  in this circuit. When we will press the first switch (the first digit of password ) the first capacitor will take charge from battery or any power source and when i will press the second switch ( second digit of password ) the second capacitor will take the half charge from the first capacitor, this circle will run up-to the last forth capacitor

STEP 4- Now we have to add the main component of the circuit, IRF540 mosfet i have choose this mosfet because the switching sensitivity of this mosfet is very high, the source pin of mosfet on ground or negative of the circuit and the gate pin to the positive pin of forth capacitor

STEP 4- Now we will add relay (5 volts) because i wants to use this circuit with AC appliances, this is optional component of this circuit if you don’t want to connects with AC appliances or devices than you don’t need to use relay

STEP 5- Also add one 1n4007 Diode on relay coil to protect the circuit from reverse current, we must have to use diode with relay in this circuit

STEP 6- We will add led to indicate the power so we also need 470ohm resistance to protect led, now add led positive on resistance and negative on drain of mosfet to anode of diode

STEP 7– The circuit is almost complete we just have to connect the circuit with the power source or battery

  • All connections details is available  in the  diagram

We have tested the circuit in two different rounds the first one we have pressed all the switches one by one and the result is good and in second round we have pressed the correct password but in a wrong sequence still the circuit not run , this circuit will run only with the correct password

watch the video for more info

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