Bimbingan Skripsi TEKNIK ELEKTRO

Digital code lock

Description.
This is a simple but effective code lock circuit that has an automatic reset facility. The circuit is made around the dual flip-flop IC CD4013.Two CD 4013 ICs are used here. Push button switches are used for entering the code number. One side of all the push button switches are connected to +12V DC. The remaining end of push buttons 2,3,6,8 is connected to clock input pins of the filp-flops. The remaining end of other push button switches are shorted and connected to the set pin of the filp-flops.
The relay coil will be activated only if the code is entered in correct sequence and if there is any variation, the lock will be resetted. Here is correct code is 2368.When you press 2 the first flip flop(IC1a) will be triggered and the value at the data in (pin9) will be transferred to the Q output (pin13).Since pin 9 is grounded the value is “0” and so the pin 13 becomes low. For the subsequent pressing of the remaining code digits in the correct sequence the “0” will reach the Q output (pin1) of the last flip flop (IC2b).This makes the transistor ON and the relay is energised.The automatic reset facility is achieved by the resistor R11 and capacitor C2.The positive end of capacitor C2 is connected to the set pin of the filp-flops.When the transistor is switched ON, the capacitor C2 begins to charge and when the voltage across it becomes sufficient the flip-flops are resetted. This makes the lock open for a fixed amount of time and then it locks automatically. The time delay can be adjusted by varying the values of R11 and C2.

Circuit diagram with Parts list.

Notes.

Assemble the circuit on a good quality PCB.
The circuit can be powered from 12V DC.
Mount the ICs on holders.
The L1 can be a 12V, 200 Ohm SPDT relay.
Capacitor C1 should be tantalum type.
The C1 and C2 must be rated at least 25V.

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FM Radio jammer

Description.
Circuit shown here can be used to jam FM radios in its vicinity. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. Working principle of the circuit is very simple and straight forward. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. Jammer circuits like this are illegal in many countries and you must assemble this circuit on your own responsibility. This circuit is intended only for fun and i request you not to misuse it.
Circuit diagram.

Notes.

For L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former.
The circuit can be powered using a 9V PP3 battery.
For extended range, use an antenna.
A 30cm long wire connected anywhere on the coil will do for the antenna.
For better performance, assemble the circuit on a good PCB.

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Water Level Control

A Water detector is a small electronic device that is designed to detect the presence of water and alert humans in time to allow the prevention of water damage. A common design is a small device that lays flat on a floor and relies on the electrical conductivity of water to decrease the resistance across two contacts. A 9 volt battery then sounds an audible alarm in the presence of enough water to bridge the contacts. These are useful in a normally occupied area near any appliance that has the potential to leak water, such as a washing machine, refrigerator with icemaker, dehumidifier, air conditioner, or water heater.

Many thing in our daily need that can be easily by implement a simple applied technology. So our life become easy and comfort. We can make anything work automatic, or work without our intervention so if we forget to run it, or to turn off it, they will be done by their shelf.

By a simple applied technology, such as electronics, we can solve many simple problem as mentioned above. With the small dimension of electronic component and small power too, we can realize our need, such as automatic lamp, remote controller, water tank level controller.

Beside all that mention above, we can make many device that valuable to our need, such as decorative lamp, amplifier, detector etc. The simple applied electronic circuits are divided in to two groups, analog and digital circuitry.

Analog electronic circuits are those in which signals may vary continuously with time to correspond to the information being represented. Electronic equipment like voltage amplifiers, power amplifiers, tuning circuits, radios, and televisions are largely analog (with the exception of their control sections, which may be digital, especially in modern units).

In digital electronic circuits, electric signals take on discrete values, which are not dependent upon time, to represent logical and numeric values. These values represent the information that is being processed. The transistor is one of the primary components used in discrete circuits, and combinations of these can be used to create logic gates. These logic gates may then be used in combination to create a desired output from an input. In this page you can find one of the circuit.

indonesia: Dengan menggunakan rangkaian pendeteksi air serta komponen inverter, D flip-flop dan rangkaian relay, maka dapat dibangun sistem kontrol pompa air untuk menjaga kondisi tangki tetap terisi air. Ketika air berada di bawah level terbawah, maka pin set dari D flip-flop akan diberi sinyal rendah sehingga keluaran Q akan tinggi dan membuat saklar relay menutup dan pompa air bekerja. Ketika air mencapai level tertinggi, maka pin clear akan diberi sinyal rendah yang akan mematikan pompa. Dengan demikian maka tangki air akan terjaga selalu dalam kondisi terisi.

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Air Ionizer

An air ionizer (or negative ion generator) is a device that uses high voltage to ionize (electrically charge) air molecules. Negative ions, or anions, are particles with one or more extra electrons, conferring a net negative charge to the particle. Cautions are positive ions missing one or more electrons, resulting in a net positive charge. Most commercial air purifiers are designed to generate negative ions.

The Geophysical Institute of the University of Alaska Fairbanks has published a paper reporting that cosmic rays normally create around 1000 negative ions and positive ions per cubic centimeter of outdoor air, the concentration being higher at higher altitudes and also near the sea. But indoor city environments may typically have half that concentration. Controlled studies have reported greater subjective well-being in an artificially negatively-ionized environment, though the reason for this is unknown.

The high electric potentials used to create air ions are achieved by using capacitors to develop a high voltage (c.20,000 volts), low-current charge at an electrode. Such voltages can also generate ozone (an energetic allotrope of oxygen), and NOx, which, even in relatively low concentrations, may irritate lung tissues, causing chest pain, coughing, throat irritation and aggravated asthma.

However, the Cedars-Sinai Medical Center, Los Angeles has stated its acceptance of anecdotal doctor's reports that the use of ionizers produces only neutral to positive reports when tried by patients suffering from respiratory problems and allergies.

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Combination Lock

D-type bistables can easily be used to make a combination lock. Using two 4013 integrated circuits, you can make a 4-digit combination lock in which the keys representing the code digits must be entered in the correct order. Pressing the key for any digit which is not part of the code RESETs all four D-types:

The D-input of the first D-type is held HIGH. When the first digit of the combination is pressed, output Q goes HIGH. If the second digit is the next key presssed, the second D-type will be SET and so on. Pressing any of the unselected keys gives a HIGH at the RESET inputs of all four bistables, and all the Q outputs revert to LOW.

Once the four digits of the code have been entered in the correct sequence, the lock ouptut goes HIGH and will remain HIGH until an unselected key is pressed. The system could be extended to provide an automatic RESET after a delay. Which type of subsystem could you use?

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Electronic Fuse

Circuit of fuse (sekring) electronic designed to operate on 230V AC with an adjustable trip current. When the current through the load exceeds a level determined by the position of the wiper on the 1k wire-wound pot, this circuit cuts off the load immediately. If S1 is open, the range is approximately 300-650 mA, and 0.8-2A when it is closed.

Note:
This circuit connects directly to 220-230V AC which can be lethal! Please do not attempt to build any of the circuits/projects unless you have the expertise, skill and concentration that will help you avoid an injury.

D1: 1N4001
T1: TIC225M
T2: BTA12-600CW

The key variable in the operation of the fuse is the voltage drop across the power resistor(s) which are connected in series with the load. This voltage drop is directly proportional to the current the load draws. When this current is low, the voltage across the resistors is also small and cannot trigger T1. At the same time the gate of T2 is fed from a little power supply built around a negative voltage regulator. T2 is conducting and the load is on.

If the current through the load then gets too high, so that the voltage created across the resistor(s) can trigger the gate of T1 through the 330R resistor and the pot: T1 starts to conduct, swiftly taking away all the current from the gate of T2. The voltage drop across T1 (MT1-MT2) will then be only 0.7 V and T2 will be firmly off. T1 stays this way all until the momentary (normally closed, "push-to-break") Reset push-button is pressed: this causes the current through T1 to drop below the hold level and forces this triac to turn off. Releasing the Reset button re-enables the current flow to and through the gate of T2, switching it on.

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Infra Red Remote Control Tester

The circuit is very effective to test the remote controls what still works or not, the remote record will be tested using infra red. Examples of the TV remote, AC and others. Please try I am sure 100% will be successful.

The workings of the circuit is very simple, when the infra red sensor receive infrared signals pin 2 sensor will produce a voltage, this voltage will drives the PNP transistor so that the LED lamp and piezo disc (BZ) is active. for the power supply you can use a 9 volt battery and then use IC 7805 or use 1.5 volt batteries x 3

Following the specification of components installed