Wiring circuit

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Monday, October 20, 2014

Three Flashing LED Doorbells For The Hearing Impaired

When the push switch is operated - the buzzer will sound and the LEDs will begin to flash. For the hearing members of the household - the buzzer acts as a regular doorbell. It also re-assures the visitor that the doorbell is working.

When the push switch is released the buzzer will stop - but the LEDs will continue to flash. The length of time they will go on flashing is set by the values of R2 & C1. With the values shown in the diagram - the LEDs will flash for a further 30 seconds or so. If you make R2 a variable resistor, you can adjust the time period. If you want longer than 30 seconds - increase the value of C1 or R2.

The last circuit will flash up to two groups of 3 LEDs in tandem. This circuit will flash the two groups alternately. The alternate flashing creates the illusion of movement - and makes the display more eye-catching. Note that - although Ive drawn the two groups of LEDs side by side - the individual LEDs can be mounted in any pattern you like.

The main difference between this circuit and the last one - is the addition of the two transistor switches. The switches will each flash up to 15 groups of 3 LEDs. And - because they are getting power directly from the battery - the LEDs will glow at their full brilliance.

Three-Flashing LED-Doorbells-Circuit-Diagram

The Support Material for these circuits includes detailed circuit descriptions - and all the information you need to adapt them to a different supply voltage. link

Friday, October 17, 2014

Extend Timer Range For The 555 Circuit Diagram

Anyone who has designed circuits using the 555 timer chip will, at some time have wished that it could be programmed for longer timing periods. Timing periods greater than a few minutes are difficult to achieve because component leakage currents in large timing capacitors become significant. There is however no reason to opt for a purely digital solution just yet. The circuit shown here uses a 555 timer in the design but nevertheless achieves a timing interval of up to an hour! The trick here is to feed the timing capacitor not with a constant voltage but with a pulsed dc voltage. The pulses are derived from the un smoothed low voltage output of the power supply bridge rectifier.

Extend Timer Range For The 555 Circuit Diagram

The power supply output is not referenced to earth potential and the pulsing full wave rectified signal is fed to the base of T1 via resistor R1. A 100-Hz square wave signal is produced on the collector of T1 as the transistor switches. The positive half of this waveform charges up the timing capacitor C1 via D2 and P1. Diode D2 prevents the charge on C1 from discharging through T1 when the square wave signal goes low. Push-button S1 is used to start the timing period. This method of charging uses relatively low component values for P1 (2.2 MΩ) and C1 (100 to 200 µF) but achieves timing periods of up to an hour which is much longer than a standard 555 circuit configuration.

Monday, September 22, 2014

Horn siren use the IT and OT transformer

Basically siren on a police patrol car and an ambulance use electronic circuit connected to the DC current. When the switch is pressed, the siren sounds immediately come out.
For those of you who own a car, or any motor you can also create a similar horn. Placement was also very practical. And if you want the flashing lights can add your own. In a series of above do not use flashing lights as the sirens sound.

Part List :
R1 = 47K
R2 = 200R
C1 = 0,02uF
C2 = 50uF 16V
C3 = 0,005uF
T1 = 2SB178 PNP transistor
S1 = Push button switch
G1 = 6-12V battery
TR1 , IT transformer is reversed. used a two-legged.
TR2 , OT output transformer OT240

How to use it is to put the above series into a box. Adjust the size to be more practical. Then insert the cable of a car or motorcycle battery voltage as described above that is 6-12 V battery into the plug. In accordance with their respective poles.
Three feet of IT transformer wrapped so as not to stick to the body of the car or motorcycle. Cover with insulation that is resistant to water. Then try if already issued a siren sounds and if so, ready for use.

Thursday, September 4, 2014

The Joule Thief

This schema is called " The Joule Thief" Because this schema can light up LEDs with low voltage that is the reason for this.If you have drained batteries you can lite up a LED by using this schema.Now I thing you can understand how much important this schema is

Wednesday, September 3, 2014

Free power from the telephone line

I think this schema will be very useful for you all to get some electricity when you are in a power cut.You can get power to light up several LED bulbs. I suppose Even a LED is very valuable when you are in the dark.after building this schema connect your schema to the telephone line through red and green wires. to get power connect your cables to + and _ lines.

This is only for educational purpose.Free schema diagrams 4U team doesnt get any responsibility of misusing this schema.

# Build this schema on a PCB

Sunday, August 31, 2014

Find the best stereo for your car

You can find out how to choose the best stereo for your car by reading this informative article!

The first thing to do is to check with your family members and friends to see what kind of stereo equipment they have in their vehicles. Referrals are sometimes the best way to find a reliable brand. The next step is to start shopping around in electronic stores to see what brands there are, what kinds of stereos are available for purchase, and what options are available. Be sure to check on what kind of a warranty that each stereo carries. Decide at this point what you want in a stereo and what you do not want. Decide what you would like to have, but what you can live without. For example, do you really need twenty radio preset buttons or can you live with only six? Beware of the extras that you may not need. If you are not going to use them, then do not buy a system with them on it. The more the gadgets, the higher the cost of the stereo, of course. Decide on how much money you can possibly spend. Talk to sales clerks and ask their opinions about the different kinds of stereos. Ask what kind they have in their own vehicles. Ask at each store whether-or-not they are authorized dealers of the products that they recommend. If your stereo needs repaired, can you take it back there and have it fixed?

Ask each sales clerk if they can demonstrate each of the models they carry? Obviously you will want to hear the differences in the stereos before you finally choose one and buy it. Find out if they will install the stereo too. Ask them the exact steps that they would take in order to accomplish the task. Find out if they have any pictures of their work. This especially pertains to the installation of the stereos speakers ans subwoofers. If you purchase a stereo and speakers that are the same size as what you currently have, then the new equipment can simply be put into the same spaces that your current equipment is in. But, if you purchase bigger speakers that will need more space to accomodate them, then these units need to be enclosed first, and then covered with carpet to match your car, truck, or van.

Stereos for your vehicle usually start out with the basic AM/FM radio unit. That is the most basic stereo you can get. Then, there are models that also have cassette players and CD players, etc. Name brand stereos and speakers are probably the better route to take when choosing. You will undoubtedly get a better sound and performance from a name brand that you can trust. Stay away from cheap models that probably sound tinny, muffled, or otherwise unnatural. The cheaper brands tend not to hold up as well as the name brands too.

Finally, the sales people will probably try to talk to you about woofers and tweeters and frequencies, etc. To put it in plain English, the woofer handles the bass frequencies and the tweeter handles the treble frequencies. If you are really interested in this, that is fine. But, if you are not, then that is all you need to know. If you dont understand the lingo of the stereo world, dont let them baffle you with foreign sounding words, technical terms, and other information that you really dont need to know.

Saturday, August 30, 2014

The Audio Video Distribution Amplifier

With the amount of equipment in home entertainment centers today the need to be able to vary the gain of the audio or video signal is needed. I found this particular schema helpful when used in conjunction with the Universal Descrambler and a Stabilizer schema I built for making copies of video tapes. It not only allowed me the ability to fine tune the video strength it also helped me increase the recorded audio which typically becomes poor when making tape copies. Circuit operation is straight forward for amplifier diagram. The second channel for the audio amplifier is made up of the same components except the other half of IC1 is used. Pin 6 & 5 are inputs and 7 is the output.

Circuit Diagram

Thursday, August 28, 2014

Understanding the workings of Vertical Deflection

Vertical deflection parts, serves to provide a sawtooth current to the vertical deflection coil so that horizontal lines are generated by applying localized horizontal deflection from the top of the screen and moves towards the bottom of the screen. Sweeping PAL system has a vertical frequency of 50 Hz and 60 Hz NTSC system. Vertical deflection circuit there are several variation, is in contrast to the horizontal deflection circuit on television almost all the same.

Broadly , the vertical deflection section comprises:

Yoke Deflection

Vertical oscillator (vertical countdown)
Ramp generator
Vertical amplifier drive
Vertical amplifier-out
Pum-up (flyback generator)
Feedback circuit
Vertical deflection coil

Countdown vertical as the vertical oscillator. Vertical count-down got input from the horizontal frequency count-down and divide in order to obtain the vertical frequency.

In this section there is a circuit called a "vertical window-counter" which serves to automatically adjust the vertical size of the frequency. Without any input video signal, vertical oscillator oscillates at a frequency of approximately 45 to 55Hz free. If then the aircraft received the system PAL video signals, vertical-counter window will lock the vertical oscillator at a frequency of 50Hz. And if a video signal NTSC system will automatically lock the vertical frequency to 60Hz

If for any damage, so the frequency can not be locked, it will cause:

Picture rolling up if the frequency is lower
Rolling down the picture if the frequency is higher.

Ramp-generator - vertical pulses from the oscillator is a square, ramp-function generator to change the shape of the signal box into a sawtooth shape. Sawtooth signal shape is determined by the value of resistor-capacitor filter contained in this section.

Vertical count-down circuit and the ramp-generator circuit is in common IC. But there are certain circuits where the ramp generator IC is in the vertical-out, ie aircraft using the TA8690 and TA8445.

Vertical amplifier Drive - serves to amplify the signal before it is fed into the vertical vertical-output amplifier. Circuits generally be one with a vertical power amplifier out.

Vertical power-amplifier Out - vertical sawtooth signal is amplified by this section to be able to supply power to the coil current sawtooth vertical deflection. The working principle of the vertical amplifier-out does not vary much with the audio power-amplifier

Pump Up (flyback generator) - applying localized electron beam vertically from the top to the bottom of the screen. To conduct further re-sweeping the electron beam must be returned with a quick way into the top layer. To do this required a strong pulse but only a moment the so-called vertical-retrace pulse, which pulse is required to establish a higher voltage supply on the vertical-out amplifier.

While doing the sweeping-vertical from the top of the screen to the bottom of the screen vertically-out circuit generally requires a voltage supply of about 25V. And at the vertical-retrace or back from the bottom to the top of the screen quickly takes a larger supply voltage of about 50V. Vertical pump-up circuit is in the vertical IC-out and serves to generate a high voltage at the moment-vertical retrace and require external components consisting of a diode and an Elko.

Vertical-drive circuit, pump-up and reinforcing vertical-out is generally a single IC package in the vertical-out.

There are several types of vertical IC-outs that do not use a pump-up circuit. Instead of the vertical-out requires two kinds of supply Vcc, the supply of low voltage and high voltage supply.