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Alex Tsekenis
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Posts posted by Alex Tsekenis
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I would check the holding current of the SCR you use, it needs to be greater than 1A in your circuit.
Why is that? The holding current is the minimum current that must flow from anode to cathode for the SCR to remain in the ON state after the gate trigger pulse dies out.
In this application the current flowing will be much much more than 1A even over short periods of time.
If anything, one would aim for an SCR with the lowest holding current.
The holding current is a specification of the SCR itself. The gate current limiting resistor (if any) will not affect that characteristic like the base resistor in a bipolar transistor switch does not affect the maximum Vc-e rating. -
It looks right to me at least the principle of it.
You can treat the circuit as having a ground potential of 1kV and a positive potential of 0V in your schematic.
That SCR of yours looks rather faint hearted...a job for my IGBTs. :P -
What I need to know is if it can accept up to 5V at 1.2A, then how much amps would it use at 4V, or 3V?
Your PSP uses a switch-mode regulator for its battery 100% sure.
5V 1.2A is the peak consumption. That is 6W.
The switch mode regulator will try to draw as much power from the battery as needed by the PSP.
So, if you use a 5V battery, the PSP will draw a maximum of 1.2A or 6W. If you use a 4V battery the PSP will still need to work as normal and will require a maximum of 6W. That is 1.5A from the battery.
In other words, the PSP internal regulator acts as a constant power load.
There is a limit to how low a voltage you can use to power the PSP. Obviously if you take the voltage too low the components in the PSP will not handle the increased current. But you will probably trigger and undervolatge lockout circuit before that.
You should not use a higher voltage power supply in order to draw less current from your battery. You could damage the PSP.
Is this what you are asking?
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Consider a microcontroller with a DMA channel. Good luck!
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No, you dont need to do that. The 12V of the amplifier is the power supply required, not the minimum input voltage. You are good to go.
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Have you switched on the power supply from the motherboard connector? Is it a 24 or 20 pin (the main connector) PSU? Does the fan rotate?
http://www.ochardware.com/articles/psuvolt/psuvolt.html
There are also cheap PSU testers...
http://www.frozencpu.com/resource/r12/Using_a_Power_Supply_Tester.html -
I am sure finding someone will not be hard, but this is a low value item and the amount work could be considerable.
The course of action I would suggest is to buy your remote remote start kit and install it. Place your extra controller with your car keys and try it for a week. After that ask yourself again if you want to go ahead. -
So you want to fit ready made circuit board x into ready made enclosure y. Assuming x will not fit into y just like that, you will need to reverse engineer x and make circuit board z that fits in y.
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Where will the existing circuit of the remote control (for central lock/unlock) go?!
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Got ya. Go back to the compiler you came from silly post bot.
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Take a picture of them please and post it here by going to reply>additional options.
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You can use a free app called Free-File-Splitter. It is very easy to use.
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Thats great, all we need now is an iphone, NOT.
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Very interesting simulator. I havent got time to test its quality/reliability yet but looking at the components' properties I see this being a great tool to test funtional units or systems. It is not a subsitute for SPICE though.
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Capacitance surface dielectric length. Low distortion capacitor.
I have a cucumber and a tomatoe. How many vegetables do I have? Please answer Kevin. -
A high frequency transistor is cheap. I have one orange and two apples. How many fruits do I have? Please answer.
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You have to digitise the audio signal using an ADC then serialise it and send it to the TX module. Then receive it at the RX module, deserialise it and use a DAC. This will make such a bad quality system for too many reasons to post here. I suggest you build a ready made audio transmitter.
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Yes, this is the job for a Data type flip flop but you can wire other flip-flops to do that as well. Anyway, your thinking is right, you have probably made a mistake with your hardware. Can you post a schematic of how you would wire your D-flip flop? Whats V+?
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I classify them as (there are always exceptions):
Electricians that install wiring and electrics in buildings from tables they have memorised.
Electronics repair technicians that repair your TV using using memorised tables and a fair amount of original thinking. These could install their own electrics so that they merely function and are not eager to expand their knowledge.
Electrical engineers. These can wire a city if you give them enough time. They will analyse the problem, devise a plan, perform research and evaluate the performance of the solution. They are mostly concerned with high power/high voltage electrical systems such as generators, transmission lines, distribution transformers, circuit breakers, motors etc.
Electronic engineers. These can repair TVs or build a computer from scratch if you give them enough time. Once again, they will follow a scientific approach to the task in hand. They are mostly concerned with lower power miniature electronics such as microprocessors, op-amps, process controllers etc.
Very often, if not always, electronic and electrical mix in complex modern systems. Electrical and Electronic Engineering degrees address this.
One can say that Electronic and Electrical Engineering is perhaps a victim of its own success. Technology has penetrated into our lives so deeply that we take it for granted. The average person does not realise how complex systems and devices are and that is bad news for engineers.
Having said all of these things, engineers possess a mindset that allows them to tackle problems from different disciplines, not just electronics or electrical. This is why e&e engineers are easily absorbed by the job market and why you find many of them in senior management positions or in research into new technologies.
I will dare say that pure engineers are born like this, not made into.
These professions, although sciences in their own right, bring in different fundamental physical sciences like chemistry, physics and maths.
I don't know your circumstances but if you are 18-30 say and have enough drive, then why not study Electrical and Electronic Engineering at a university? Very often undergraduates get job offers long before graduation. You can even go and work at a company for 1 year and gain industrial experience. Apprenticeships in companies is another good way to learn and become professional. It is my belief that you will need to study more theory on your own this way, but this applies for university to some extent.
Good luck! -
I promise I saw this cover project in Elektor much more recently.
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Hello Kevin,
If a normal person, not a general purpose silicon diode, has one bipolar transistor in each hand, and two capacitors on each foot how many components does the person have? Microwave magnetron voltage multiplier...
Thank you
Alex -
The output power of a wind generator is a function of wind speed, blade design and number of blades,dimensions, air temperature and efficiency of the generator and the system as a whole.
You can increase the power output if you increase the efficiency of the generator. This cone be done with more powerful magnets yes (Faraday's law). I am not so sure about the number of coils though...
Whatever the case, the companies that designed the motors have already thought of these things. -
Buy her a ring instead.
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You are lucky.
Buy this Elektor issue (a few punds) as it is a good magazine for hobbyists. The issue is December 2006 of Elektor (UK publication) www.elektor.com
What do they say? :P
Trigger an SCR to switch a negative voltage
in Power Electronics
Posted
I think you have missed the point of Riccardos circuit. He is trying to dump the energy in the capacitor in the coil. The peak current will be several 10s of amperes after some time after the gate trigger pulse.The current will then decay as the capacitor discharges until it falls below the holding current at which point the scr will switch off with some energy left in the capacitor. R1 will then slowly reacharge the capacitor. Riccardo is not using the 1kV suppky and R1 to supply current to the coil directly. He probably doesnt want to switch it off anyway before the capacitor is discharged.
The holding current for a thyristor of the size of the BT152 is in the 10s of mA. And for a much larger thyristor it will be about a few hundends of mA. In any case much lower than 1A. Is there even a thyroistor with such a holding current?
The two transitor model does not explain the physics in a thyristor, just the latching action. Holding current does not depend on the gate resistor, it is a fundamental specification of the device that depends on temperature.