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Friday, December 27, 2013

Invisible Broken Wire Detector

Portable loads such as video cameras, halogen flood lights, electrical irons, hand drillers, grinders, and cutters are powered by connecting long 2- or 3-core cables to the mains plug. Due to prolonged usage, the power cord wires are subjected to mechanical strain and stress, which can lead to internal snapping of wires at any point. In such a case most people go for replacing the core/cable, as finding the exact location of a broken wire is difficult.

In 3-core cables, it appears almost impossible to detect a broken wire and the point of break without physically disturbing all the three wires that are concealed in a PVC jacket. The circuit presented here can easily and quickly detect a broken/faulty wire and its breakage point in 1-core, 2-core, and 3-core cables without physically disturbing wires. It is built using hex inverter CMOS CD4069.

Gates N3 and N4 are used as a pulse generator that oscillates at around 1000 Hz in audio range. The frequency is determined by timing components comprising resistors R3 and R4, and capacitor C1. Gates N1 and N2 are used to sense the presence of 230V AC field around the live wire and buffer weak AC voltage picked from the test probe. The voltage at output pin 10 of gate N2 can enable or inhibit the oscillator circuit.

When the test probe is away from any high-voltage AC field, output pin 10 of gate N2 remains low. As a result, diode D3 conducts and inhibits the oscillator circuit from oscillating. Simultaneously, the output of gate N3 at pin 6 goes ‘low’ to cut off transistor T1. As a result, LED1 goes off. When the test probe is moved closer to 230V AC, 50Hz mains live wire, during every positive half-cycle, output pin 10 of gate N2 goes high.

Thus during every positive half-cycle of the mains frequency, the oscillator circuit is allowed to oscillate at around 1 kHz, making red LED (LED1) to blink. (Due to the persistence of vision, the LED appears to be glowing continuously.) This type of blinking reduces consumption of the current from button cells used for power supply. A 3V DC supply is sufficient for powering the whole circuit.

Circuit diagram:

Invisible Broken Wire Detector Circuit Diagram

AG13 or LR44 type button cells, which are also used inside laser pointers or in LED-based continuity testers, can be used for the circuit. The circuit consumes 3 mA during the sensing of AC mains voltage. For audio-visual indication, one may use a small buzzer (usually built inside quartz alarm time pieces) in parallel with one small (3mm) LCD in place of LED1 and resistor R5. In such a case, the current consumption of the circuit will be around 7 mA.

Alternatively, one may use two 1.5V R6- or AA-type batteries. Using this gadget, one can also quickly detect fused small filament bulbs in serial loops powered by 230V AC mains.
The whole circuit can be accommodated in a small PVC pipe and used as a handy broken-wire detector. Before detecting broken faulty wires, take out any connected load and find out the faulty wire first by continuity method using any multimeter or continuity tester.

Then connect 230V AC mains live wire at one end of the faulty wire, leaving the other end free. Connect neutral terminal of the mains AC to the remaining wires at one end. However, if any of the remaining wires is also found to be faulty, then both ends of these wires are connected to neutral. For single-wire testing, connecting neutral only to the live wire at one end is sufficient to detect the breakage point.

In this circuit, a 5cm (2-inch) long, thick, single-strand wire is used as the test probe. To detect the breakage point, turn on switch S1 and slowly move the test probe closer to the faulty wire, beginning with the input point of the live wire and proceeding towards its other end. LED1 starts glowing during the presence of AC voltage in faulty wire. When the breakage point is reached, LED1 immediately extinguishes due to the non-availability of mains AC voltage.

The point where LED1 is turned off is the exact broken-wire point. While testing a broken 3-core rounded cable wire, bend the probe’s edge in the form of ‘J’ to increase its sensitivity and move the bent edge of the test probe closer over the cable. During testing avoid any strong electric field close to the circuit to avoid false detection.
Author: K. Udhaya Kumaran
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Thursday, December 26, 2013

A Handy Pen Torch

This easy to construct “Handy pen torch” electronic circuit and low component count, uses two power white LEDs for lighting. Low volt (4.8V dc) supply available from the built in rechargeable Ni-Cd battery pack is first converted into two channel (independent) constant current sources by two pieces of the renowned precision adjustable shunt regulator chip LM334 (IC1 and IC2). Around 25mA at 3.6 volt dc is available at the output of these ICs.

A regulated dc supply is used to drive two power white LEDs D4 and D6. Resistors R3 and R5 limits the output current (and hence the light output) of IC1 and IC2 circuits respectively. Besides these components, one red color LED (D2) is included in the main circuit which works as a battery charging supply input indicator. Resistor R1 limits the operating current of this LED.

Pen Torch Electronic Circuit Schematic

Circuit Project: Handy Pen Torch circuit

Diode D1 works as an input polarity guard cum reverse current flow preventer. Capacitor C1 is a simple buffer for circuit stabilization. After succesful construction, preferably on a small piece of general purpose PCB, enclose the whole circuit in a suitable and attractive pen torch cabinet. If necessary, drill suitable holes in the cabinet to attach the dc socket, on/off switch and the input indicator etc.

In prototype, commonly available 4.8 volt/500mah Ni-Cd battery pack (for cordless telephones) is used. One very simple but reliable ac mains powered battery charger circuit for the handy pen torch is also included here. Basically the pen torch circuit is a constant current charger wired around Transistor T1 (BC636), powered by a 12v/350mA step down transformer and associated componentsD1, D2 and C1.

AC mains powered battery charger for the pen torch


Circuit Project: Handy Pen Torch circuit


Unregulated 12 volt dc available from the input power converter circuit, comprising step down transformer(TRF), rectifier diodes (D1,D2) and filter capacitor (C1), is fed to T1 through a current limiting resistor R1. Grounded base PNP transistor T1 here works as a constant current generator. With 22 ohm resistor for R1, the charging current available at the output of the charger is near 50mA.

Red LED (D3) provides a fixed voltage reference to the base of T1, with the help of resistor R2. (During charging process, Diode D1 in the main circuit prevent reverse current flow from the battery pack when charging input supply is absent.) After construction of the pen torch circuit, fit the assembled unit inside a small plastic enclosure for safety and convenience.

Circuit Source: DIY Electronics Projects
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Wednesday, December 25, 2013

LED Bike Light

On my mountain bike I always used to have one of those well-known flashing LED lights from the high street shop. These often gave me trouble with flat batteries and lights that fell off. As an electronics student I thought: “this can be done better”. First I bought another front wheel, one which has a dynamo already built in the hub. This supplied a nice sine wave of 30 Vpp (at no load). 

With this knowledge I designed a simple power supply. The transistors that are used are type BD911.These are a bit of an over-kill, but there were plenty of these at my school, so that is why I used them. Something a little smaller will also work. The power supply is connected to an astable multi-vibrator. This alternately drives the front light and the rear light. The frequency is determined by the RC time-constant of R3 and C3, and R2 and C4. This time can be calculated with the formula: t = R3×C3 = 20×103×10×10-6 = 0.2 s You can use a 22k (common value) for R2 and R3, that doesn’t make much difference. On a small piece of prototyping board are six LEDs with a voltage dropping resistor in series with each pair of LEDs.

LED Bike Light Circuit Diagram


Such a PCB is used for both the front and the rear of the bike. Of course, you use white LEDs for the front and red ones for the rear. The PCB with the main circuit is mounted under the seat, where it is safe and has been working for more than a year now. There are a few things I would change for the next revision. An on/off switch would be nice. And if the whole circuit was built with SMD parts it could be mounted near the front light. This would also be more convenient when routing the wiring. Now the cable from the dynamo goes all the way to the seat and from there to the front and rear lights.

Source :  www.ecircuitslab.com


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Tuesday, December 24, 2013

Rain Sound Effects Generator

This rain sound effects generator circuit simulates the rain noise and may be used in the field of electronic music and radio shows.As a noise source we use a germanium diode that is directly polarized then is amplifier by a single stage amplifier in order to obtain an acceptable audio level.

A high-pass filter with an adjustable lower limit, built with P1 and C3, allow coverage of the entire range of sound effects from light rain and to torrential rain.The current consumption is low so you can use a 9V battery. Instead of BC107 you can use any NPN transistor.

Rain Sound Effects Circuit Schematic

Circuit Project: Rain Sound Effects Generator circuit
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Monday, December 23, 2013

It is due to the insulation feature of the antenna

It is

due to the insulation feature of the antenna of cell phone jammer .
Product Type: licensed are already C at the end (K790c (quotation Lively), the M608c (quotations Lively video)), parallel imports are already i at the end (such as the K790i, M600i). Although it is

the leader in the industry, Nokia parallel and, like Motorola, Samsung, as the momentum of rapid, the main reason is OK, the difference between the water is not obvious, usually only about two or

three hundred dollars, and weak The difference is difficult to inspire the majority of consumer desire to buy. However, among the four brands, Nokia parallel is most difficult to identify, there is

no way to start in appearance, can only be found to plant date, the model code or the details to identify the authenticity. cell phone jammer can work effectively and act on the shielding in the

location.It is the biggest feature and advantage of cell phone jammer
The differential between the Nokia phone lines, water points. No. Enquiry: enter * # 0000 # to view the version number, manufacture date, model code, enter * # 92702689 # to view the motherboard

factory date information. IEMI yards Enquiries: Nokia mobile phones directly press the "* # 06 # on your phone, the phone will appear 15 IEMI yards, 7-8 bit code is the origin code, control is as

follows: 10 = Finland (Finland), 20 = German ( Germany), 30 = South Korea (Korea). Directly call the Nokia customer service telephone and Internet inquiries. Identification methods in line water

Motorola. Although not as large as the parallel product line of Samsung, Motorolas V3 (quote Lively video panorama), E680i. (Quote Lively video panorama). It is the location where cell phone

jammer is needed.
The A1200 (quotations Lively video) and several of its products, all crack, occupying a great share of the gray market, of course, Motorola cell phone line, water is relatively good to identify, in

appearance, features, accessories, etc. Direct identification. The differential between the Motorola phone lines, water points. Appearance: licensed to work fine, relatively rough parallel,

keyboard strokes are engraved. The software features: You can check the version number on the machine. GPRS, not directly to the Internet. Accessories: the parallel headset mostly not original,

rough work, easy to fade. In addition, funeral expenses random gift CD picture is fuzzy, and are generally VCD discs posing. OK water identification method other brand papers. More working

efficiency of the antenna and host of cell phone jammer can be ensured.
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Sunday, December 22, 2013

Power Supply Monitor Memory Protector Circuit Diagram

This Power Supply Monitor-Memory Protector Circuit Diagram detects low-voltage supply conditions, down to 0.6 V. Dl sets the trip point of the circuit. The circuit is useful to protect memory circuits from accidental writes in the event of power-supply low-voltage conditions, which cause other circuits to turn off, etc. Response time is about 700 ns. R6 provides some hysteresis to ensure clean transitions.

Power Supply Monitor-Memory Protector Circuit Diagram

Power Supply Monitor-Memory Protector Circuit Diagram

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Saturday, December 21, 2013

Basic 12V Output To 5V Buck Regulator Circuit Diagram

This is 12V Output To 5V Buck Regulator Circuit Diagram. By adding a flyback winding to a buck-regulator switching converter (see the figure), wliich is essentially a 5-V supply with a 200-mA output capability, a 12-V output ) can be produced. 

The flyback winding on the main inductor (forming transformer Tl) enables an additional low- dropout linear regulator (IC2) to create the 12-V output voltage that`s needed to program EEPROMs.The required input voltage is 8 to 16 V.


12V Output To 5V Buck Regulator Circuit Diagram

12V Output To 5V Buck Regulator Circuit Diagram

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Friday, December 20, 2013

Current to Voltage Converter Circuit Diagram

A filter removes the dc component of the rectified ac, which is then scaled to RMS. The output is linear from 40 Hz to 10 kHz or higher.

 Current to Voltage Converter Circuit Diagram

Current to Voltage Converter Circuit Diagram

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Thursday, December 19, 2013

Network Voltage Indicator

Using this schematic can be made a network voltage indicator electronic circuit. If the input voltage is present across the network, the optocoupler transistor is open, T1 is blocked and controlled rectifier, Th1, is in a state of conduction. Since both terminals of the piezoelectric buzzer is at the same potential, buzzer is off. If voltage disappears, the transistor T1 enters the conduction and thus makes the terminal of buzzer to be put on the ground (maintains thyristor conduction state).

Circuit Project: Network voltage indicator electronic circuit

In this situation, there is a sufficiently large potential difference across the buzzer and D5s to determine that these two elements to indicate AC power loss, both audible and visual. By pressing the reset button current is interrupted by Th1, so thyristor enter in blocking state and the other terminal of the buzzer is connected to ground.
Circuit Source: DIY Electronics Projects
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Wednesday, December 18, 2013

Simple US Style Siren Circuit

The circuit described here can create three different ‘US-style’ siren sounds: police, ambulance and fire engine. The desired sound can be selected using switch S1. The circuit can be used in toys (such as model vehicles), as part of an alarm system, and in many other applications. For use in a toy, a BC337 is an adequate device for driver T5, since it is capable of directly driving a 200mW (8Ω) loudspeaker.

 

Circuit diagram :

US-Style Siren-Circuit diagram

Simple US-Style Siren Circuit Diagram

In this case the current consumption from a 9 V power supply is around 140 mA. If a louder sound is required, a BD136 is recommended: this can drive a 5W (8Ω) loudspeaker. The current consumption from a 12 V supply will then be about 180mA. If still more volume is desired, then T5 (a BD136) can be used as a first driver stage, and a 15W (8Ω) loudspeaker can be connected via output transistor T6.

Here an AD162 or an MJ2955 can be used, which, for continuous operation, must be provided with cooling. The peak current consumption of the circuit will now be about 500mA with a 12V power supply. Capacitor C1 is not required for battery operation.

Author : L.  Libertin - Copyright : Elektor

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Tuesday, December 17, 2013

AUTOMATIC HEAT DETECTOR

      This circuit uses a complementary pair comprising npn metallic transistor T1 (BC109) and pnp germanium transistor T2 (AC188) to detect heat (due to outbreak of fire, etc) in the vicinity and energise a siren. The collector of transistor T1 is connected to the base of transistor T2, while the collector of transistor T2 is connected to relay RL1.
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     The second part of the circuit comprises popular IC UM3561 (a siren and machine-gun sound generator IC), which can produce the sound of a fire-brigade siren. Pin numbers 5 and 6 of the IC are connected to the +3V supply when the relay is in energised state, whereas pin 2 is grounded. A resistor (R2) connected across pins 7 and 8 is used to fix the frequency of the inbuilt oscillator. The output is available from pin 3.

     Two transistors BC147 (T3) and BEL187 (T4) are connected in Darlington configuration to amplify the sound from UM3561. Resistor R4 in series with a 3V zener is used to provide the 3V supply to UM3561 when the re- lay is in energised state. LED1, connected in series with 68-ohm resistor R1 across resistor R4, glows when the siren is on.

     To test the working of the circuit, bring a burning matchstick close to transistor T1 (BC109), which causes the resistance of its emitter-collector junction to go low due to a rise in temperature and it starts conducting. Simultaneously, transistor T2 also conducts because its base is connected to the collector of transistor T1. As a result, relay RL1 energises and switches on the siren circuit to produce loud sound of a firebrigade siren.
      Lab note. We have added a table to enable readers to obtain all possible sound effects by returning pins 1 and 2 as suggested in the table.
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Monday, December 16, 2013

Simple motor Circuit diagram


 


Hi everyone today Im going to give you a very simple and important circuit.We all know about the motor but we dont know how to make a simple motor so here is the way to make a simple motor circuit diagram 
What you want is a magnet battery and a coil.And try to fix it as it shows  




Note

# Use insulated coils 
# Use 1.5 V battery
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