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qbone

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  1. Hey guys, I have been told that there exist some kind of standard time values used to calculate how long manual assembly of a PCB would take in general. Is should be a list with time values of how long it will take to manually insert components, solder etc. I have searched on google and all I can find is this manual that cost 1000$ and might aswell be bogus, but ofc I am looking for something "open source" aka. free :) Does any of you know these standard times or know where I can find a table with time values? Kind Regards Mads Henriksen
  2. Thanks Hero999, was hoping to find one thats wasnt SMD, but I'm just gonna settle with that :-)
  3. I live in Denmark and the suppliers available are Mouser, Farnell, RS-Components
  4. Hey Guys I just found my old Tyco Rebound RC car, and wanted to test it. It turns out that one side of the wheels can only go one way, and I have traced the problem to a transistor controlling the motor in the RC car. The Transistor is a 2SD2166R made by the company Rohm. I have found the datasheet, but I am very inexperienced in finding replacement part. http://pdf1.alldatasheet.com/datasheet-pdf/view/35903/ROHM/2SD2166R.html That's the Datasheet. Does any of you know where I can buy a new one, or if there is a part I can use as replacement which is maybe more accessible? I'm not sure if it matters but The two motors are controlled by 8 of transistors of the above type. I dunno if they have to be matched or whatever. /Mads
  5. What I'm trying to do is make the voltage rise and fall within some boundaries.. a MAX voltage and a MIN (offset) voltage. so that I can adjust the span where the voltage should rise and fall, and adjust the offset. an example; I want to be able to make the voltage rise between 500mV and 3V. Kinda like the comon 4mA - 20mA applications outthere, only where the sensor is an LDR and the output is voltage.
  6. Anyone? I would think that I would need something like a current or voltage summer in order to create the offset, but I gotta make it without the use of opamps. For the span im not really sure. I would really appreciate it if someone could point me in a direction. Ignore the schematic in the OP, its wrong and outdated :) EDIT: I have now tried something that seems to work, atleast somewhat, however, I still have a problem with the use of an opamp. Is there a way to make a DC voltage follower without the use of an opamp? And perhaps even so I can eliminate the problem with my opamps max output being only 3,5V when it's supplied with 5V and same problem with offset in an opamp.
  7. Ok, thanks for, but that is only a quick sketch of the _old_ design. I need to build a new one where I can adjust offset and span, and for that I am asking if anyone have a few pointers as to what I should read up on. If possible it need to be designed without the use of opamps. :-\
  8. Hey guys. Im rather new to this forum, but have been looking around for a while for something that might help me. I got an assignment from my boss that I should design a new circuit. The circuit need to be controlled by an LDR and work so that when it gets dark the voltage increase and when it gets dark the voltage decrease. The one we have now works somewhat alright, it adjusts the voltage output between 0 and whatever max value is chosen. I have attached a picture of the current schematic. Now I need to change it a little so that we can adjust and offset and change the span.. And this is where I need help hehe. At first I made a circuit with opamps setting offset with a summer circuit, but this is no good, cause as it turns out I gotta stick to discrete components so it doesnt become too expensive and too big. Now.. What im looking for is not necessarily a complete design, but more some directions as to what I should look for and read about. I am an apprentice in an electronics form, so I wanna learn :) So what im looking for is a way to set offset with - I dunno, a transistor circuit of some kind? And also a way to adjust the span so that we can change how bright it should be before the output reaches maximum. I apoligize for my bad english grammar, please don't hesitate to ask if I need to clarify something.
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