Usually they work, if it is correct to type the code on the keypad. Electric locks, which are placed in this article, operate on a different principle. The key for them is a small socket with the pins, for example, finger lamp. Socket is the base — it installed schema key. When enabled, a lock is triggered. And, as we have commotional lead wires, to reveal the secret of the castle will not succeed.
Figure 1 shows a diagram of the lock with led key. When it is inserted into the electric castle, formed by a diode bridge. The relay coil DC is applied to the rectified voltage of the power source, and the contact closes.
In another diagram (Fig. 2) when adding a key, forms a rectifier with voltage doubler. Relay in this circuit is triggered when the voltage on the source of the power is doubled.
In the circuit shown in figure 3, the relay has one half wave of the AC voltage power source. Relay is not included. If you connect the key with the capacitor at the moments of arrival of the reverse half-cycle when the diode is locked, relay “fueled” by the energy of the capacitor. Thus, the average for the period the voltage is doubled and the relay contact is closed.
And finally, in the last diagram (Fig. 4) as the key is used a transformer with two coils wound on a ferrite ring wire of PEL 0,1. When you connect the transformer the voltage on the relay network exceeds approximately 2 times (the ratio of the number of turns of the windings of the transformer is 1:2), and it works.
In all schemes, the relay includes a solenoid or other actuator. You can use any relay with an operating current of 20-30 mA to the appropriate voltage.
The resistor R1 (Fig. 1, 3, 4) sew-10 limits the current in a circuit if you close the socket lock.
The device is powered by a low power transformer (5— 10 W), for example, the output from the tube radio, with the secondary voltage of 36 V. you Can use the secondary winding of the bell housing. Then it will be enough to insert the key into the lock slot and press the call button.
If desired, the lock can be done smarter. For this turnkey installing more than one nest, and 5-10. One of them is connected to the circuit, the other false. This greatly impedes a clue to the secret of the castle.
Vladimir GUREVICH, Kharkov