Roma has developed a small E17 LED Light Bulb

Roma has developed a small LED bulb "LDA4L-G-E17" can support E17 lamp holder, compare with the original LED bulbs such as 12 volt LED lights, new products reduce the size of the power part, the shade of the hemispherical shape is more nearly spherical. LED light source module use the COB construct without mirror, the shape almost identical to  old-fashioned small krypton bulb to achieve 180°light distribution angle.

Prior to the disadvantage of small LED bulb is less luminous part of the light distribution angle narrow, dark horizontal and supply side. The brightness of the new product is equivalent to a 25W mini krypton bulb. The shade is made of the proliferation of Roma self-developed material that can be issued does not point to the warmth of light. The bulb the total luminous flux of 265lm, the power consumption of 4W. The light color than incandescent light color. Design life (the luminous flux dropped to 70% of the initial time) is approximately 40,000 hours. Pricing is open, expect the actual price of less than 2000 yen.

By the way, I konw where to buy the LED lighting such as LED light and best led flashlight at low price,

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How to fix a tube light simply

This post shows how to fix a tube light with its parts correctly.lots of people asked me about this that is why I thought to give you some thing like this.now I think you will be able to solve your problems.

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Build a 500W Low Cost 12V to 220V Inverter

Attention: This Circuit is using high voltage that is lethal. Please take appropriate precautions

Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.

How to calculate transformer rating
The basic formula is P=VI and between input output of the transformer we have Power input = Power output

For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18.3 = 220v*1
So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.

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Designing a Grid Tie Inverter Circuit

A grid tie inverter works quite like a conventional inverter, however the power output from such inverter is fed and tied with the AC mains from the utility grid supply. As long as the mains AC supply is present, the inverter contributes its power to the existing grid mains supply, and stops the process when the grid supply fails.

The concept is indeed very intriguing as it allows each of us to become an utility power contributor. Imagine each house getting involved in this project to generate overwhelming amounts of power to the grid, which in turn provides a passive income source to the involved residences. Since the input is derived from the renewable sources, the income becomes absolutely free of cost.

Making a grid tie inverter at home is considered to be very difficult as the concept involves some strict criteria to be observed, not following may lead to hazardous situations.

The main few things that must be observed are:

The output from the inverter must be perfectly synchronized with the grid AC.

The output voltage amplitude and frequency as mentioned above must all correspond with the grid AC parameters.

The inverter should switch OFF instantly in case the grid voltage fails.

In this post I have tried to present a simple grid-tie inverter circuit which according to me takes care of all the above requirements and delivers the generated AC into the grid safely without creating any hazardous situations.

Lets try to understand the proposed design (exclusively developed by me) with the help of the following points:

 Again, as usual our best friend, the IC555 takes the center stage in the entire application. In fact only because of this IC the configuration could become apparently so very simple.

Referring to the circuit diagram, the IC1 and IC2 are basically wired up as a voltage synthesizer or in a more familiar terms a pulse position modulators.

A step down transformer TR1 is used here for supplying the required operating voltage to the IC circuit, and as well as for supplying the synchronization data to the IC, so that it can process the output in accordance with the grid parameters.

Pin#2 and pin#5 of the both the ICs are connected to the point after D1, and via T3 respectively, which provides the frequency count and amplitude data of the grid AC to the ICs respectively.



The above two information provided to the ICs prompts the ICs to modify their outputs at the respective pins in accordance with these information.

The result from the output translates this data into well optimized PWM voltage thats very much synchronized with the grid voltage.

IC1 is used for generating positive PWM, while IC2 produce negative PWMs, both work in tandem creating the required push pull effect over the mosfets.

The above voltages are fed to the respective mosfets, which effectively converts the above pattern into a high  current fluctuating DC across the involved step up transformer input winding.

The output of the transformer converts the input into a perfectly synchronized AC, compatible with the existing grid AC.

While connecting the TR2 output with the grid, connect a 100 watt bulb in series with one of the wires. If the bulb glows, means the ACs are out of phase, reverse the connections immediately and now the bulb should stop glowing ensuring proper synchronization of the ACs.

Assumed PWM Waveform (bottom trace) at the Outputs of the ICs

Parts List

All resistors = 2K2
C1 = 1000uF/25V
C2,C4 = 0.47uF
D1,D2 = 1N4007,
D3 = 10AMP,
IC1,2 = 555
MOSFETS = AS PER APPLICATION SPECS.
TR1 = 0-12V, 100mA
TR2 = AS PER APPLICATION SPECS
T3 = BC547
INPUT DC = AS PER APPLICATION SPECS.

WARNING: THE IDEA IS BASED SOLELY ON IMAGINATIVE SIMULATION, VIEWERS DISCRETION IS STRICTLY ADVISED.


After receiving a corrective suggestion from one of the readers of this blog Mr. Darren and some contemplation, it revealed that the above circuit had many flaws and it wouldnt actually work practically.

The revised design is shown below, which looks much better and a feasible idea.

Here a single IC 556 has been incorporated for creating the PWM pulses.
One half of the IC has been configured as the high frequency generator for feeding the other half IC which is rigged as a pulse width modulator.

The sample modulating frequency is derived from TR1 which provides the exact frequency data to the IC so that the PWM are perfectly dimensioned in accordance with the mains frequency.

The high frequency makes sure the output is able to chop the above modulation information to precision and provide the mosfets with an exact RMS equivalent of the grid mains.

Finally, the two transistors make sure that the mosfets never conduct together rather only one at a time, as per the mains 50 or 60 Hz oscillations.

Parts List

R1,R2,C1 = select to create around 1 kHz frequency

R3, R4,R5,R6 = 1K

C2 = 1nF

C3 = 100uF/25V

D1 = 10 amp diode

D2, D3, D4, D5 = 1N4007

T1, T2 = as per requirement

T3, T4 = BC547

IC1 = IC 556

TR1, TR2 = as suggested in the previous section design

The above circuit was analyzed by Mr. Selim and he found some interesting flaws in the circuit. The main flaw being the missing negative PWM pulses of the AC half cycles. The second fault was detected with the transistors which did not seem to isolate the switching of the two mosfets as per the fed 50 Hz rate.

The above idea was modified by Mr. Selim, here are the waveform details after the modifications. modifications:

Waveform Image:

CTRL is the 100 Hz signal after the rectifier, OUT is from PWM from both halve waves, Vgs are the gate voltages of the FETs, Vd is the pickup on the secondary winding, which in sync with CTRL/2.

Disregard the frequencies as they are incorrect due low sampling speeds (else it gets too slow on the ipad). At higher sampling freqs (20Mhz) the PWM looks quite impressing.

To fix the duty cycle to 50% at around 9kHz, I had to put a diode in.

Regards,

Selim

For enabling the detection of the negative half cycles, the control input of the IC must be fed with both the half cycles of the AC, this can be achieved by employing a bridge rectifier configuration.

Heres how the finalyzed circuit should look according to me. The transistor base is now connected with a zener diode so that would hopefully enable the transistors to isolate the mosfet conduction such that they conduct alternately  in response to the 50 Hz pulses at the base T4.

Recent  Updates from Mr. Selim

Hello Swags,

I keep reading your blogs and continue experimenting on the breadboard.
I have tried the zener-diode approach (no-luck), CMOS gates and, much better, op-amps worked best. Ive got 90VAC out of 5VDC and 170VAC from 9VDC at 50Hz, I believe its in sync with the grid ( cant confirm as no oscilloscope). Btw the noise goes if you clamp it with a 0.15u cap. on the secondary coil.

As soon as I put a load on the secondary coil, its voltage drops to 0VAC with only a slight increase in input DC amps. The Mosfets dont even try to draw more amps. Perhaps some mosfet drivers like IR2113 (see below) could help?

Although in high spirits, I feel that PWM might not be as straight forward as hoped. It definitely is good to control torque on dc motors at low pwm freqs. However when the 50 Hz signal gets chopped at higher freq, it for some reason looses power or the PWMd mosfet cant deliver the needed high amps on the primary coil to keep the 220VAC going under load.

Ive found another schematic which is very closely related to yours, except PWM. You might have seen this one before.

The link is on http://www(dot)electro-tech-online(dot)com/alternative-energy/105324-grid-tie-inverter-schematic-2-0-a.html

The power handling circuit is an H drive with IGBTs (we could use mosfets instead). It looks like it can deliver the power across.

It looks complicated but actually is not too bad, what do you think? I will try to simulate the control circuit and let you how it looks.

Regards,

Selim

Sent from my iPad

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Top 5 Reasons for a New Auto Sound System

If you are a fan of David Letterman, Im sure youve seen and heard his nutty and often hilarious top 10 lists. He has become famous for them and they have been often imitated but never quite aptly duplicated by many around the world. I have no intentions of trying to claim or ever hope to be as funny as Letterman but I would love to create a top 5 list of why you need a new auto sound system. The sad part is that some of this may ring true for many, if not, I bet it will at least make you smile.

5) You really hate your neighbors and secretly hope that enough loud, late night thumping from your car will convince them to move. Admittedly not the kindest reason for the need of a new auto sound system but if youve had some of my previous neighbors I am fairly certain that it isnt too bad of an idea. Just be careful not to shake too much or they may be leaving part of their automobiles behind.

4) Because you saw it on Ebay and like Weird Al Yankovich you just cant seem to refuse when it comes to last minute bargains in the worlds largest garage sale. The truth of the matter is that Ebay can be an excellent resource as far as auto sound systems go. It is important however, to remember that you really need to hear the system before you spend your hard earned money buying it and a lot of time and/or money on the installation of the sound system you select. For that reason Ebay may not be the best choice for your particular needs.

3) Because youre tired of crummy speakers that seem to play static more than music and make more popping and snapping sounds than your old fashioned popcorn popper. Speakers are often only a small part of how your sound system runs. Chances are if you are currently having speaker problems an entirely new auto sound system is going to be in order to insure that all the problems are fixed and solved to your complete satisfaction.

2) Because your Aunt Ethel who has cataracts has a better auto sound system than you. Believe me I know this one stings a little, especially when it hits home. We all hate to think that someone that is older has a more technologically hip and sound product than we do. We often like to kid ourselves into thinking that we live on the cutting edge of technology when that is probably far from the case. Aunt Ethel probably has the kicking sound system she does so that it can be heard without the assistance of miracle ear so keep that in mind before you pull all of your hair out.

And the number 1 reason you should get a new auto sound system is that the 8-trac went out of fashion long before your first child was born. Even though youve clung to the past, it has finally met its limitations of usefulness and it is time to move along and embrace the wonderful world of modern technology and what it can mean to you and the time you and your family spend riding in your vehicle. Hope you had a great smile for the day!

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How to Make a Solar Inverter Circuit

power is its simplicity. It is almost completely solid state, from the photovoltaic cell to the electricity delivered to the consumer. Whether the application is a solar calculator with a PV array of less than 1 W or a 100 MW grid-connected PV power generation plant, all that is required between the solar array and the load are electronic and electrical components. Compared to other sources of energy humankind has harnessed to make electricity, PV is the most scalable and modular. Larger PV systems require more electri- cal bussing, fusing and wiring, but the most complex component between the solar array and the load is the electronic component that converts and processes the electricity:

 the inverter. In the case of grid-tied PV, the inverter is the only piece of electronics needed between the array and the grid. Off-grid PV applications use an addi- tional dc to dc converter between the array and batteries and an inverter with a built-in charger. In this article we discuss how inverters work, includ- ing string, or single-phase, and central, 3-phase inverters; explore major inverter functions, key components, designs, controls, protections and com- munication; and theorize about future inverter technology

get here

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How to Build a Simple Electronic Incubator Thermostat

An electronic incubator thermostat circuit shown in this article is not only simple to build but is also easy to set and acquire exact tripping points at various different set temperature levels. The setting may be completed through two discrete variable resistors. The sensing range is quite good from 0 to 110 degrees Celsius.

Switching a particular load at different threshold temperature levels doesn’t necessarily need complex configurations to be involved in an electronic circuit. Here we discuss a simple construction procedure of an electronic incubator thermostat.

This simple electronic incubator thermostat will very faithfully sense and activate the output relay at different set temperature levels from 0 to 110 degree Celsius.

The conventional electromechanical temperature sensors or thermostats are not very efficient due to the simple reason that they cannot be optimized with accurate trip points.

Normally these types of temperature sensor or thermostats fundamentally use the ubiquitous bimetal strip for the actual tripping operations. When the temperature to be sensed reaches the threshold point of this metal, it bends and buckles.

Since the electricity to the heating device passes through this metal, it’s buckling causes the contact to break and thus power to the heating element is interrupted - the heater is switched off and the temperature starts falling. As the temperature cools, the bimetal starts straightening to its original form. The moment it reaches its previous shape, the electricity supply to the heater is restored through its contacts and the cycle repeats.

However, the transition points between the switching are too long and not consistent and therefore not reliable for accurate operations.

The circuit presented here is absolutely free from these drawbacks and will produce comparatively high degree of accuracy as far the upper and the lower tripping operations are concerned.

Parts List

R1 = 2k7,

R2, R5, R6 = 1K

R3, R4 = 10K,

D1---D4 = 1N4007,

D5, D6 = 1N4148,

P1 = 10K,

VR1 = 200 Ohms, 1Watt,

C1 = 1000uF/25V,

T1 = BC547,

T2 = BC557,

IC = 741,

OPTO = LED/LDR Combo.

Relay = 12 V, 400 Ohm, SPDT.

Circuit Description

We know that every semiconductor electronic component changes its electrical conductivity in response to the varying ambient temperature. This property is exploited here to make the circuit work as a temperature sensor and controller.

Diode D5 and transistor T1 together form a differential temperature sensor and interact greatly with each other with changes in the respective surrounding temperature.

Also since D5 acts as the reference source by staying at the ambient temperature level should be kept as far as possible from T1 and in open air.

Pot VR1 may be used externally to optimize the reference level set naturally by D5.

Now assuming D5 is at a relatively fixed temperature level (ambient), if the temperature in question around T1 starts rising, after a particular threshold level as set by VR1, T1 will begin to saturate and gradually start conducting.

Once it reaches the forward voltage drop of the LED inside the opto-coupler, it will start glowing correspondingly brighter as the above temperature rises.

Interestingly as the LED light reaches a particular level, further set by P1, IC1 picks this up and instantly switches its output.

T2 along with relay also respond to the IC’s command and respectively actuate to trip off the load or the heat source in question.

How to go About with the Opto-Coupler?

  It’s very simple. Cut a piece of general purpose board about 1 by 1 inch.

Bend the LDR leads near its “head.” Also take a green RED LED, bend it just as the LDR (See figure and Click to Enlarge).

Insert them over the PCB so that the LED lens point is touching the LDR sensing surface and are face to face.

Solder their leads at the track side of the PCB; do not cut off the remaining excess lead portion.

Cover the top with an opaque lid and make sure its light proof. Preferably seal off the edges with some opaque sealing glue.

Let it dry. Your home made opto-coupler is ready and may be fixed over the main circuit board with its leads orientations done as per the electronic incubator thermostat circuit schematic.

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