Friday, September 19, 2014
Build a Auto Anti Hijack Alarm Circuit Diagram



Friday, January 10, 2014
Super Hi Fi Headphone Amplifier Circuit Diagram
Super Hi-Fi Headphone Amplifier Circuit Diagram

Most mobile phones on the market today or a single CPU
S40, nokia mobile phone operating system developed by the face of low-end customers, support kjava the development, its processor efficiency is not high, low memory, screen size 128 * 128. S60, is based on the Symbian operating system, that is, before the epoc processor arm9 high processing efficiency, considerable memory, screen size is 208 * 176 support both kjava and C + + development. S90, is a handheld device, the Symbian operating system, but robust, equivalent to a PDA. In fact, says the technology to the S40 with the S60 is the difference between system platforms, like WIN98 now WIN2000 but the phone unlike the PC, the screen size is indeed a mark. The technical review of Cell Phone Jammers is important too.In order to prevent dust and foreign matter into the sound chamber, can be affixed inside the enclosure dust network, for the beautiful, the sound hole on the outside can be affixed to the nickel plate, PC tablets, and other decorative pieces, small mesh diameter of the nickel plate 0.3mm, nickel plate, inside the enclosure can not affixed to the dust network. speaker after tune the low frequency part of the main impact of ringtones, high frequency part is smaller, you can not do the requirements. In order to get good bass, no component interference on the motherboard, you can use the antenna bracket and motherboard with affixed foam speaker Tune closed after the formation of the sound chamber in order to get more awesome bass vibration effects, speakers, family speaker.
Give priority to the purchase and the successful capital increase, will promote Symbian to the next stage of growth. Today, shareholders and unified commitment to a strong proof of the Symbian are fully capable to meet the needs of current and future industry development. Yoshiaki Kushiki, president of Panasonic Mobile Communications, said: "Panasonic is fully exercised the right of first refusal to the Psion shares. This shows our strong commitment to the independence of Symbian through a broad, balanced and equity basis to maintain this independence is critical This will be conducive to the Symbian operating system in the mobile phone industry to maintain its objective criteria, and continue to receive long-term support and backing of a number of manufacturers and network operators. " The individual quality assurance can not assure the quality of Cell Phone Jammers totally.
We must consider the draft between the various shell upper and lower shell along the mold more than 3 degrees, metal decorative pieces around the draft to be more than 5 degrees. Appearance of the side is the outer contour surface of the phone, a good curve out surface, described line be sure to close the ID of the wireframe ID creative respect the basic accomplishment of structural engineers and lines but also try smoothing as much as possible uniform change of curvature, draft angle should be taken into account, if the ID of the line pull draft angle and structural requirements are inconsistent, and ID consultation appearance by the structure in the description line directly to fix the draft angle of the contour lines, if the plastic shell to retain the draft angle is larger ID of the creative destruction plastic mold, you might consider doing the four sides of line spaces, after all, the phone is a high-end consumer goods, this investment is worth. It is to strengthen the quality control of Cell Phone Jammers .
Electrical Schematic Symbols
Electrical Schematic Symbols:
Electrical circuit schematic symbols are graphical sign, that is used to design electronic, electrical circuit schematic diagram. There is a quite adequate collection of symbol for electrical, electronic circuit. You can use this high quality schematic symbols to design your own schematic circuit diagram. Download high quality electrical schematic symbols image.![]() |
| High Quality Electrical Schematic Symbols |
Click on the image of Schematic Symbols to enlarge.
This circuit schematic symbols are for educational purposes only, not for any industrial use.
Thursday, December 26, 2013
Battery Equality Monitor
R1 = 2.K
R2 = 4.7K
R3 = 39K
R4 = 39K
R5 = 1.5K
R6 = 1.5K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = 3mm Red LED
D2 = 3mm GreenLED
B1 = DC 12 Volt
B2 = DC 12 Volt
Tuesday, December 24, 2013
cell phone jammer will have the normal dissipation as the working time accumulates
error". If there is no similar "system error" and then the lattice machine. Various GSM, CDMA cell phones including PAS, 3G can be shielded through cell phone jammer .
Is to set the error causes the device is not working: do not have lattice machine, as long as you restore the factory settings, Note that this command only to restore the settings, different from
the lattice machine, after the resumption of business card holder, pictures, documents, etc. all still there, just set to restore some friends set incorrectly I do not know how to change it back,
you can use this command. After the above five ways to exclude, if the cell phone is still a problem, often re-start, the machine can not start or turn on the power but you can not enter the
standby or standby process only bright for a few seconds, the cell phone on their own restart repeatedly after turned off state, the Department of the serious problems to the general grid machine.
cell phone jammer will have the normal dissipation as the working time accumulates.
Note: in the grid before formatting the data before backup: No matter what way lattice machine, format, all cell phones C drive is restored to the factory when the state, of course, include your
text messages and cell phone book, so the formatting before they want to keep the program or other documents should be retained. Available reader to operate. To determine in advance you want to
back up data, such as SMS, Contacts, Calendar, and the software installed. Lattice machine should be backed up? Firstly I should say is not backed up as possible, because often you backup is the
wrong place. Backup some of the card holder must be on the line, the personality machine will only backup the card holder and procedures for the classification of documents.
Mostly software presentations and to use the E text. Mostly software presentations and use their softwares home page link. Mostly software presentations and to use the E text. General decryption
introduction can be used to open the handwritten, and sometimes there will bear the registration code of the software. Software to back up data, which will bear the registration information of the
software. Can extract the first on the PC Take a look, if there are * sis suffix software to unlock and install the SIS file sent to your cell phone, if the decompression is open, which have "META
-INF folder also There are a lot of other files, the Java software, general JAR format of java is a special format, suffix is *. jar, RAR compression software that can be mistaken for a rar format
on a PC, you do not unpack. cell phone jammer of high quality will gain more and more customers.
Sunday, December 22, 2013
Dual Power Amplifier
Description
The schematic is shown in Figure 1, and is based on the PCB version. All unnecessary functions have been disabled, so it functions as a perfectly normal power amplifier. While the board is designed to take two TDA7293 ICs, it can naturally be operated with only one, and the PCB is small enough so that this is not an inconvenience. A LED is included to indicate that power is available, and because of the low current this will typically be a high brightness type.

Construction
Power Supply
WARNING: This power supply circuit requires experience with mains wiring. Do not attempt construction unless experienced, capable and suitably qualified if this is a requirement where you live. Death or serious injury may result from incorrect wiring.
Connect to a suitable power supply - remember that the supply earth (ground) must be connected! When powering up for the first time, use 100 ohm 5W "safety" resistors in series with each supply to limit the current if you have made a mistake in the wiring. If available, use a variable bench supply - you dont need much current to test operation, and around 500mA is more than enough. If using a current limited bench supply, the safety resistors can be omitted. Do not connect a speaker to the amplifier at this stage!
Friday, December 20, 2013
Simple Voltage Booster
Simple Voltage Booster Circuit Diagram :
Notes.
- The component values are not very specific here.We can use any NPN power transistors like D1616,2N 3055,C2236,SL 100 etc for Q1 and Q2.
- The transformer can be any center tapped 5A transformer with a 7:1 winding ratio.
- The diodes can be 1N 914 ones.
- In fact you can easily assemble the circuit from the components in your electronics junk box.
- By experimenting on the tranformer winding you can get different boost ratios.
- For high current (around 5A) games use 2N 3055 transistor or more powerful Darlington pairs for Q1 and Q2.
Wednesday, December 18, 2013
Build a high volt supply Circuit Diagram

Monday, December 16, 2013
Two Line Intercom Cum Telephone Line Changeover
Thursday, October 10, 2013
Wire Tracer Receiver
The prototype used a high impedance loudspeaker from a telephone handset, and this worked remarkably well. The purpose of P1 is to adjust the amplification. At the highest amplification, the wire energized by the transmitter can be traced from several tens of centimeters away. A direct electrical connection is therefore not required. However, it is important that you hold the ground connection (earth) in your hand.Tuesday, October 8, 2013
Model Railway Turnout Control
This situation persists until C1 is fully charged. No more current flows after that, so the triac does not receive any gate current and switches off. If the input is set low, a negative current flows briefly via C1. It can flow through D2, but not through D1. T4 is switched on now, and the other turnout coil is energised. This circuit takes advantage of the fact that triacs can be triggered by negative as well as positive gate currents. If the turnout coils are energised for too long, you should reduce the value of C1.
If they are not energised long enough, increase the value of C1. The TIC206D can handle several ampères, so it can easily drive just about any type of turnout coil. You can also use a different type of triac if you wish. However, bear in mind that the TIC206 requires only 5 mA of gate current, while most triacs want 50 mA. That will cause the switching times to become quite short, so it may be necessary to reduce the value of R1.
Sunday, October 6, 2013
Passive RIAA Preamplifier
Friday, October 4, 2013
Mini High Voltage Generator Circuit
Here’s a project that could be useful this summer on the beach, to stop anyone touching your things left on your beach towel while you’ve gone swimming; you might equally well use it at the office or workshop when you go back to work. In a very small space, and powered by simple primary cells or rechargeable batteries, the proposed circuit generates a low-energy, high voltage of the order of around 200 to 400 V, harmless to humans, of course, but still able to give a quite nasty ‘poke’ to anyone who touches it.
Quite apart from this practical aspect, this project will also prove instructional for younger hobbyists, enabling them to discover a circuit that all the ‘oldies’ who’ve worked in radio, and having enjoyed valve technology in particular, are bound to be familiar with. As the circuit diagram shows, the project is extremely simple, as it contains only a single active element, and then it’s only a fairly ordinary transistor. As shown here, it operates as a low-frequency oscillator, making it possible to convert the battery’s DC voltage into an AC voltage that can be stepped up via the transformer.
Using a centre-tapped transformer as here makes it possible to build a ‘Hartley’ oscillator around transistor T1, which as we have indicated above was used a great deal in radio in that distant era when valves reigned supreme and these was no sign of silicon taking over and turning most electronics into ‘solid state’. The ‘Hartley’ is one of a number of L-C oscillator designs that made it to eternal fame and was named after its invertor, Ralph V.L Hartley (1888-1970). For such an oscillator to work and produce a proper sinewave output, the position of the intermediate tap on the winding used had to be carefully chosen to ensure the proper step-down (voltage reduction) ratio.
Here the step-down is obtained inductively. Here, optimum inductive tapping is not possible since we are using a standard, off-the-shelf transformer. However we’re in luck — as its position in the centre of the winding creates too much feedback, it ensures that the oscillator will always start reliably. However, the excess feedback means that it doesn’t generate sinewaves; indeed, far from it. But that’s not important for this sort of application, and the transformer copes very well with it.
The output voltage may be used directly, via the two current-limiting resistors R2 an R3, which must not under any circum-stances be omitted or modified, as they are what make the circuit safe. You will then get around 200 V peak-to-peak, which is already quite unpleasant to touch. But you can also use a voltage doubler, shown at the bottom right of the figure, which will then produce around 300 V, even more unpleasant to touch. Here too of course, the resistors, now know as R4 and R5, must always be present. The circuit only consumes around a few tens of mA, regardless of whether it is ‘warding off’ someone or not! If you have to use it for long periods, we would however recommend powering it from AAA size Ni-MH batteries in groups of ten in a suitable holder, in order not to ruin you buying dry batteries.
Circuit diagram:
Warning!
If you build the version without the voltage doubler and measure the output voltage with your multimeter, you’ll see a lower value than stated. This is due to the fact that the waveform is a long way from being a sinewave, and multimeters have trouble interpreting its RMS (root-mean-square) value. However, if you have access to an oscilloscope capable of handling a few hundred volts on its input, you’ll be able to see the true values as stated. If you’re still not convinced, all you need do is touch the output terminals...
To use this project to protect the handle of your beach bag or your attachecase, for example, all you need do is fix to this two small metallic areas, quite close together, each connected to one output terminal of the circuit. Arrange them in such a way that unwanted hands are bound to touch both of them together; the result is guaranteed! Just take care to avoid getting caught in your own trap when you take your bag to turn the circuit off!
Copyright : Elektor Electronics 2008
Wednesday, October 2, 2013
Simple Voltmeter

Monday, September 30, 2013
Magic Lights
Both counters of each of these ICs have been cascaded to obtain 8 outputs from each. The outputs from IC2 and IC3 are connected to IC4 through IC7 which are BCD to 7-segment latch/decodor/driver ICs. Thus we obtain a total of 14 segment outputs from each of the IC pairs consisting of IC4 plus IC5 and IC6 plus IC7. While outputs from former pair are connected to pin No. 1 of all the 14 bi-colour LEDs via current limiting resistors, the ouputs of the latter pair are similarly connected to pin No.3 of all the bi-colour LEDs to get a magical dancing lights effect.Saturday, September 28, 2013
100W Inverter Circuit Diagram Schematic
Here is a 100 Watt inverter circuit using minimum number of components. I think it is quite difficult to make a decent one like this with further less components.Here we use CD 4047 IC from Texas Instruments for generating the 100 Hz pulses and four 2N3055 transistors for driving the load. The IC1 Cd4047 wired as an astable multivibrator produces two 180 degree out of phase 100 Hz pulse trains.
These pulse trains are preamplified by the two TIP122 transistors.The out puts of the TIP 122 transistors are amplified by four 2N3055 transistors (two transistors for each half cycle) to drive the inverter transformer.The 220V AC will be available at the secondary of the transformer. Nothing complex just the elementary inverter principle and the circuit works great for small loads like a few bulbs or fans.If you need just a low cost inverter in the region of 100 W, then this is the best.
Circuit Diagram:
100 Watt Inverter Circuit Diagram
Parts:
P1 = 250K
R1 = 4.7K
R2 = 4.7K
R3 = 0.1R-5W
R4 = 0.1R-5W
R5 = 0.1R-5W
R6 = 0.1R-5W
C1 = 0.022uF
C2 = 220uF-25V
D1 = BY127
D2 = 9.1V Zener
Q1 = TIP122
Q2 = TIP122
Q3 = 2N3055
Q4 = 2N3055
Q5 = 2N3055
Q6 = 2N3055
F1 = 10A Fuse
IC1 = CD4047
T1 = 12-0-12V
Transformr Connected in Reverse
Notes:
- A 12 V car battery can be used as the 12V source.
- Use the POT R1 to set the output frequency to50Hz.
- For the transformer get a 12-0-12 V , 10A step down transformer.But here the 12-
- 0-12 V winding will be the primary and 220V winding will be the secondary.
- If you could not get a 10A rated transformer , don’t worry a 5A one will be just
- enough. But the allowed out put power will be reduced to 60W.
- Use a 10 A fuse in series with the battery as shown in circuit.
- Mount the IC on a IC holder.
- Remember,this circuit is nothing when compared to advanced PWM
- inverters.This is a low cost circuit meant for low scale applications.
Design tips:
- The maximum allowed output power of an inverter depends on two factors.The
- maximum current rating of the transformer primary and the current rating of the driving
- transistors.
- For example ,to get a 100 Watt output using 12 V car battery the primary current will be
- ~8A ,(100/12) because P=VxI.So the primary of transformer must be rated above 8A.
- Also here ,each final driver transistors must be rated above 4A. Here two will be
- conducting parallel in each half cycle, so I=8/2 = 4A .
- These are only rough calculations and enough for this circuit.
Source : www.extremecircuits.net
Thursday, September 26, 2013
4 Bit Analogue to Digital Converter
- R1:R2 = 1:2;
- R3:R4:R5 = 1:2:4;
- R6:R7:R8:R9 = 1:2:4:8.
This type has a totem-pole output. The non-inverting inputs should be interlinked and connected to the tap of a a divider consisting of two 10 kΩ resistors across the supply lines. It is essential that the converter is driven by a low-resistance source. If necessary, this can be arranged via a suitable op amp input buffer. The converter draws a current not exceeding 5 mA.
Tuesday, September 24, 2013
Mobile Travel Charger Circuit
Here is an ideal Mobile charger using 1.5 volt pen cells to charge mobile phone while traveling. It can replenish cell phone battery three or four times in places where AC power is not available. Most of the Mobile phone batteries are rated at 3.6 V/500 mA. A single pen torch cell can provide 1.5 volts and 1.5 Amps current. So if four pen cells are connected serially, it will form a battery pack with 6 volt and 1.5 Amps current. When power is applied to the circuit through S1, transistor Q1 conducts and Green LED lights.
Most of the Mobile phone batteries are rated at 3.6 V/500 mA. A single pen torch cell can provide 1.5 volts and 1.5 Amps current. So if four pen cells are connected serially, it will form a battery pack with 6 volt and 1.5 Amps current. When power is applied to the circuit through S1, transistor T1 conducts and Green LED lights. When T1 conducts T2 also conducts since its base becomes negative. Charging current flows from the collector of T1. To reduce the charging voltage to 4.7 volts, Zener diode ZD is used. Resistor R4,and R5 allows 20 mA charging current. If more current is required, reduce the value of R4 to 100 Ohms so that with in 20 to 30 minutes battery will become fully charged. Points A and B are used to connect the charger with the mobile phone. Use suitable pins for this and connect with correct polarity.
Circuit diagram :
Mobile Phone Travel Charger Circuit Diagram
Parts:
R1 = 1K
R2 = 470R
R3 = 4.7K
R4 = 270R
R5 = 27R
C1 = 100uF-25V
D1 = Green LED
D2 = 4.7V/1W Zener
B1 = 1.5Vx4 Cells
S1 = On/Off Switch
Q1 = BC548
Q2 = SK100
The circuit comes from here.
Sunday, September 22, 2013
Low Power FM Transmitter
NOTE: A few people have had trouble with this circuit. The biggest problem is not knowing if it is even oscillating, since the frequency is outside the range of most simple oscilloscopes. See Project 74 for a simple RF probe that will (or should) tell you that you have a useful signal at the antenna. If so, then you know it oscillates, and just have to find out at what frequency. This may require the use of an RF frequency counter if you just cannot locate the FM band.
Description
The circuit of the transmitter is shown in Figure 1, and as you can see it is quite simple. The first stage is the oscillator, and is tuned with the variable capacitor. Select an unused frequency, and carefully adjust C3 until the background noise stops (you have to disable the FM receivers mute circuit to hear this).
Because the trimmer cap is very sensitive, make the final frequency adjustment on the receiver. When assembling the circuit, make sure the rotor of C3 is connected to the +9V supply. This ensures that there will be minimal frequency disturbance when the screwdriver touches the adjustment shaft. You can use a small piece of non copper-clad circuit board to make a screwdriver - this will not alter the frequency.
The frequency stability is improved considerably by adding a capacitor from the base of Q1 to ground. This ensures that the transistor operates in true common base at RF. A value of 1nF (ceramic) as shown is suitable, and will also limit the HF response to 15 kHz - this is a benefit for a simple circuit like this, and even commercial FM is usually limited to a 15kHz bandwidth.
Capacitors
All capacitors must be ceramic (with the exception of C1, see below), with C2 and C6 preferably being N750 (Negative temperature coefficient, 750 parts per million per degree Celsius). The others should be NPO types, since temperature correction is not needed (nor is it desirable). If you cannot get N750 caps, dont worry too much, the frequency stability of the circuit is not that good anyway (as with all simple transmitters).
How It Works
Q1 is the oscillator, and is a conventional Colpitts design. L1 and C3 (in parallel with C2) tunes the circuit to the desired frequency, and the output (from the emitter of Q1) is fed to the buffer and amplifier Q2. This isolates the antenna from the oscillator giving much better frequency stability, as well as providing considerable extra gain. L2 and C6 form a tuned collector load, and C7 helps to further isolate the circuit from the antenna, as well as preventing any possibility of short circuits should the antenna contact the grounded metal case that would normally be used for the complete transmitter.
The audio signal applied to the base of Q1 causes the frequency to change, as the transistors collector current is modulated by the audio. This provides the frequency modulation (FM) that can be received on any standard FM band receiver. The audio input must be kept to a maximum of about 100mV, although this will vary somewhat from one unit to the next. Higher levels will cause the deviation (the maximum frequency shift) to exceed the limits in the receiver - usually ±75kHz.
With the value shown for C1, this limits the lower frequency response to about 50Hz (based only on R1, which is somewhat pessimistic) - if you need to go lower than this, then use a 1uF cap instead, which will allow a response down to at least 15Hz. C1 may be polyester or mylar, or a 1uF electrolytic may be used, either bipolar or polarised. If polarised, the positive terminal must connect to the 10k resistor.
Inductors
The inductors are nominally 10 turns (actually 9.5) of 1mm diameter enamelled copper wire. They are close wound on a 3mm diameter former, which is removed after the coils are wound. Carefully scrape away the enamel where the coil ends will go through the board - all the enamel must be removed to ensure good contact. Figure 2 shows a detail drawing of a coil. The coils should be mounted about 2mm above the board.
For those still stuck in the dark ages with imperial measurements (grin), 1mm is about 0.04" (0.0394") or 5/127 inch (chuckle) - you will have to work out what gauge that is, depending on which wire gauge system you use (there are several). You can see the benefits of metric already, cant you? To work out the other measurements, 1" = 25.4mm
NOTE: The inductors are critical, and must be wound exactly as described, or the frequency will be wrong.
The nominal (and very approximate) inductance for the coils is about 130nH.This is calculated according to the formula ...
L = N² * r² / (228r + 254l)
... where L = inductance in microhenries (uH), N = number of turns, r = average coil radius (2.0mm for the coil as shown), and l = coil length. All dimensions are in millimetres.
Pre-Emphasis
It is normal with FM transmission that "pre-emphasis" is used, and there is a corresponding amount of de-emphasis at the receiver. There are two standards (of course) - most of the world uses a 50us time constant, and the US uses 75us. These time constants represent a frequency of 3183Hz and 2122Hz respectively. This is the 3dB point of a simple filter that boosts the high frequencies on transmission and cuts the same highs again on reception, restoring the frequency response to normal, and reducing noise.
The simple transmitter above does not have this built in, so it can be added to the microphone preamp or line stage buffer circuit. These are both shown in Figure 3, and are of much higher quality than the standard offerings in most other designs.
Rather than a simple single transistor amp, using a TL061 opamp gives much better distortion figures, and a more predictable output impedance to the transmitter. If you want to use a dynamic microphone, leave out R1 (5.6k) since this is only needed to power an electret mic insert. The gain control (for either circuit) can be an internal preset, or a normal pot to allow adjustment to the maximum level without distortion with different signal sources. The 100nF bypass capacitors must be ceramic types, because of the frequency. Note that although a TL072 might work, they are not designed to operate at the low supply voltage used. The TL061 is specifically designed for low power operation.
The mic preamp has a maximum gain of 22, giving a microphone sensitivity of around 5mV. The line preamp has a gain of unity, so maximum input sensitivity is 100mV. Select the appropriate capacitor value for pre-emphasis as shown in Figure 3 depending on where you live. The pre-emphasis is not especially accurate, but will be quite good enough for the sorts of uses that a low power FM transmitter will be put to. Needless to say, this does not include "bugging" of rooms, as this is illegal almost everywhere.
I would advise that the preamp be in its own small sub-enclosure to prevent RF from entering the opamp input. This does not need to be anything fancy, and you could even just wrap some insulation around the preamp then just wrap the entire preamp unit in aluminum foil. Remember to make a good earth connection to the foil, or the shielding will serve no purpose.



