Electronic Combination Lock Circuit Diagram

Home circuits ua3730 combination lock modified.

Electronic combination lock circuit diagram. Electronic combination lock circuit. 20 36 22 october 2013 this circuit based on the ua3730 ic with some modifiactions to produce a combination lock for a safe. As you can see if we do not press the switch b it will not change any more of ic. Using the special purpose ls7220 digital lock ic the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time.

It will move the output from pin 3 to pin 2. It responds only to the roght sequence of four digits that are keyed in remotely. Some circuits would be illegal to operate in most countries and others are dangerous to construct and should not be attempted by the inexperienced. This simple code lock circuit described here is of an electronic combination lock for daily use.

In this condition output o0 pin 2 of counter ic1 is high while all other outputs are low. Electronic circuit schematics note that all these links are external and we cannot provide support on the circuits or offer any guarantees to their accuracy. Key code lock switch circuit diagram. The circuit consists of a stepdown transformer whose input is ac supply of 230v and 50hz.

This circuit illustrates the use of xor exclusive or gates as bit comparators. Digital keypad combination lock this simple circuit is the electronic version of the combination lock. One transistor electronic code lock system circuit design. Four of these xor gates compare the respective bits of two 4 bit binary numbers each number entered into the circuit via a set of switches.

In the stepdown transformer number of windings in the primary coil is less than the number of windings in the secondary coil. This electronic circuit is one of the simplest code lock circuit one can make easily in their home this circuit uses one transistor a relay and a few passive components in it the logic of this circuit is also very simple even this circuit is simple it works really fine and efficient for a simple cupboard or shelf lockers. It causes the positive voltage at the input of ic1 in next step. This could be the circuit diagram of a easy electronic combination lock by using ic ls 7220 this circuit may be applied to activate a relay for controlling on off any device each time a preset combination of 4 digits are pressed the circuit may be operated from 5v to 12v.

If a wrong key is touched it resets the lock. At power on capacitor c2 connected to pin 15 of ic1 charges to high level through 820 kilo ohm resistor holding the counter in the reset state. The lock code can be set by connectiong the line wires to the pads a b c and d in the figure.