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Thanks friends
As you see i have electret microphone and transistor amplifiers, VCC is 5V and my output is "signal" wire, usually most of frequncies and speaking sounds are on my output, i want to use 10 KHZ, below 8 khz and above 11 khz signals should be as less as possible. finally i wan't to...
Hi friends
I need a way to detect 10 KHZ sound, I use simple electret microphone with pair of 2N2222 transistors as aplifier, the problem is with other frequency noises on it, i want to filter other sounds below 8 khz and upper than 11 khz, can someone suggest me a filter or circuit?
I use...
I have changed crystal with rc osc and it's ok. the board is smd and main problem is with acc meter chip that is in QFN package.
I have 8 board for test in real condition, i had 4 test untill now, 2 of them with epoxy resin and 2others with silicon glue, in first test resin broked and caused...
Hi friends
I have a project with heavy mechanical shock, my board has a microcontroller, acc meter sensor, crystal, v-regulator and some resistor and caps. my problem is heavy mechanical shock that is about 5000 G!
heavy acc cause by explosion that is for throwing my board, it will damage board...
sorry for my bad english, when you turn on and off a lamp much times in short time it cause damage the lamp, i want to understand it about switching power supply, let me ask more simple:
i have a circuit that has a switching power supply, some 1 watt leds and a key, what is better to do for me...
Hi friends
I want to use some 12V and 2A ( or about 5A too ) switching power supply to use with some 1W LED to lighting room but i'm not sure in which way the powe supply life will be more:
1- using on-off key befor my power adaptor ( 220V ac goes through key to power supply when i want turn on...
as my customer said i changed this circuit from base, i used a selector key tu have 4 different light with 4 different 5W resistor, i'll try this circuit when i'll be free too:)
best regards for you attention kam :)
thanks for answer
I have uased 20K pot before 1K and i had same problem, my resistors are 5W resistor, 2n3055 max collector current is 75A and in this circuit max current is 1A, main problem is POT!! anyway i try 50K too :)
Thanks
Hi friends
I have a 12W LED ( 12X1W ), I need a circuit to control it's light, i use this circuit but after few hours pot heat goes up and makes problem. what do you suggest to control light of 12W led with potentiometer?
Regards
This is one of them:
https://downtownclub.webs.com/cheapmetaldetector.htm
there are some other article like this and a video that shows how to build it!
metal detector with cd/dvd, calc and headphone??!!!!
Hi friends
I saw some article about building metal detector with cd, dvd, calculator and headphone!!
i made it but i didn't hear any sound, anybody have some experience with this kind of metal detectors? can this detectors work?!!! i don't...
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