I have some PCBs from which I would like to remove the WHITE TEXT on the component side as well as the copper layer side.. As it is hiding some tracks.. I do not want to scratch it as the mask will come off..

What chemical will remove the texts.??

Please help me out with designing a message display board one of this kind here
http://www.datacareindia.com/leddisplaysystem/destinationdisplayboards.htm

I always wonder how are the LEDs interfaced to the MCU

I mostly work with microcontrollers and timers..

My main need for buying an oscilloscope is for decoupling the power supply ripples due to switching voltage regulators or other reasons, to measure output timing and voltage of of timers and microcontrollers and etc.
I may also use it in detecting RF & EMI interferences ..

Don't forget with digital oscilloscopes sampling rate is just as important as bandwidth. Technically, to see a waveform properly in one go you need a sampling rate 10x higher than the bandwidth. So a 100Mhz scope needs 1GSa/sec, now you can get by with less if the waveform is repetitive, because the scope can interpolate samples to fill in the details, but if you are are trying to trace glitchy behavior you need the higher sample rate.

I am looking forward to buy this Oscilloscope here http://www.metravi.com/prod_detail.php?prod=DSO-5100A
here is the datasheet of it
http://www.metravi.com/PDF/DSO%20Catalogue.pdf

What is the bare minimum voltage that can be supplied to a NE555 timer to run properly ?

I would like to use 555 to an application where there is only 4.5v available from 3 x 1.5v batteries.

Hello..!!

I would like to buy an oscilloscope to work with power management and with microcontrollers.

I have read many articles, all says that you should have an oscilloscope with bandwidth five times more than the frequency you want to measure.

Please suggest me with an oscilloscope bandwith which one to go for.?
I thought of getting an 100Mhz .

I need to write programs for some PICs . Please suggest me a good c based compiler like AVR Studio or arduino..


OR if I get the PICKIT 2 programmer does it contain any compiler and tutorial..??

Another thing is that please tell me some SSR which are common and are mostly available.. load will be 500W maximum

depends on how much you want to use it (switching on/off)

if it's a lot of switching on and off. avoid relays... a solid state relay would be a good alternative for a lot of switching...

out of curiosity, what is you're doing?

I am converting my bedroom electrical switch board to digital. That is , instead of the piano switch I will be using tactile push buttons to switch LIGHTS, FAN and etc. Later in few days I will add a IR sensor and a remote to control them with an IR remote..

I am making a push button switch board for switching ON or OFF A.C. load.

Please tell which way it be reliable, using RELAYS, TRAICS or SCR...??
Personally I do not want to use relays, so if I use a TRIAC, then how should I connect it to arduino .
Can I connect the GATE of the TRIAC directly to arduino ar I should use a MOC3011 optoisolator..??

What if I do this..??




I found another circuit where they are doing it in this way..



Another similar circuit here

those are ready to use modules..

I know about them..

But I would like to control it with arduino for other reasons..... You can say a kind of home automation..

Yes its a single PHASE ceiling fan...

After some search I found that some people use MOC3011 with an optocupler..

here is a circuit which I found..

I would like to use arduino to control the household fan speed which runs on 230V A.C.  ...

How will I control the fan speed from the PWM outputs of the arduino board..??

What components should I use to fire a triac for the regulation..??

Is it possible that the second pair of xbees ( the pair on antenna tracker and the one connected to the computer) are 2mW series 2 2.4 ghz xbees and the first pair is (the one in the drone and on the antenna tracker) is the 900 Mhz xbees..??