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    IR Transmitter/Receiver

    I hope the inventive idea is not the IR thermometer  :-\
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    IR Thermometer

    When we say infra-red, we mean all the frequencies below what the human eye can see. That is very wide band of infinite frequencies or wavelengths. The IR receiver or transmitter in a remote control system use very different wavelengths than an IR thermometer. For this very simple reason, you...
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    Limiting Mains current.

    Hi, Taking the worst case, where you have 2 turns 0.5m dia. , your coil will have an inductance of about 4uH. I have assumed an ESR of 50mOhms including connectors. Once you trigger the IGBT, assuming no voltage drop there, you will get 340 Volts across your inductor. Current will start rising...
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    Limiting Mains current.

    I see. Much better now. Yes that will complicate driving the IGBT but not too much. It comes down to whether you want electrical isolation of the control circuit or not. For example, if your control circuit is powered by some lab bench power supply that has earthed  negative terminals then you...
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    need help creating a simple circuit.

    Hi, Find a cheap 9V, 10VA or so transformer (maybe one of those that you can choose the output voltage), connect all the bulbs in parallel and then to the transformer. Merry Christmas!  8) Alex
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    Limiting Mains current.

    See attached diagram with notes. This is definitely a coil gun.  ;) You have already connected the ground to mains and broken the isolation the 12V transformer provides by grounding the 1000uF capacitor. If I were you I would use an isolated control section powered from the 12V trafo and leave...
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    Remove the Sell/Buy electronics - Job offer/requests section?

    I think a posting rule on minimum required posts will be very effective, say 10 posts required for Sell/Buy and 5 posts for HV. Spammers dont have the time to post 5 times to get one advert out. Maybe it is worth seeing how this is managed in other forums too.
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    Limiting Mains current.

    Yes an isolating transformer will limit the current for several reasons. However you should consider that only if you require electrical isolation in your system. It is an overkill otherwise. 100W is a very big transformer to use. you can power your TV at the same time as charging the capacitor ...
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    Remove the Sell/Buy electronics - Job offer/requests section?

    Maybe if you placed a rule on the system that doen't allow you to post there if you have say under 10 posts?
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    IR Thermometer

    Agree with Hero. I am posting to advise you not to give away great ideas for free  :) Regards, Alex
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    Limiting Mains current.

    The power dissipated would be for a fraction of a second and it will repeat every time you want to recharge. The rectified UK mains voltage should be about 340 Volts peak. To limit the maximum input current to 1.5 A you could use a 226 Ohm resistor or the closest E series equivalent. Very...
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    Limiting Mains current.

    Hi Riccardo, You must use a resistor. The series capacitor would also be discharged at the beginning thus acting like a 'short circuit'. Although the capacitor would present capacitive reactance as you say, at switch-ON the waveform is a 'step' signal going from 0 to whatever the mains voltage...
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    Making PCB's

    Oh that's not good.  :-\ To whom?
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    Making PCB's

    Hi Hero, Too poor for any real PCB contouring in my opinion. But great for drilling afterwards. I found a great page that shows the capabilitities of this method using magazine paper and a laminator. The 25
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    stripboards?

    Come on now... Maybe it blends well with flux fumes. :P MrUmunhum - Any local store will have stripboards or matrix boards, from China, England/ Europe, some 'Arab country' or maybe from America who knows. Just ask in local shops. I assume that this is for a simple electronics project. I...
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    Making PCB's

    Hi Hero, 25
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    Making PCB's

    Ah...do you think I have gone soft gogo? :'( Once you have built a dozen PCBs on your own, your priorities might change from pride#1 to repeatability and quality#1 which is still pride from a different viewpoint. The ideal would be to get professional quality at home but that requires a big...
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