Jump to content
Electronics-Lab.com Community

Nick Mulder

  • Content Count

  • Joined

  • Last visited


About Nick Mulder

  • Rank
    Advanced Member
  1. pdf is 3.3MB hmmmm here's the PSU pages though... Too small ?? :P
  2. Hello, My stereo amp (NAD 317) when I turned it on started making a ratcheting up buzzer noise which would last about half a second then 'start up' (some relay would click on and all was well)... This lasted a few days until this weekend when I was going to have a look at it but today it no longer switches on or anything, power = nothing ... Take a look at the photo - I'm getting AC past the fuses at 'C' (checked the fuses to be sure) - and 15v DC at both left and right amplifiers +VL ('B' is left) - I dont see any negative DC though on the -VL wires (is there meant to be -ve ?). I figure
  3. The square wave Its the output of an LDR, which is conditioned into the red line signal which is then scaled appropriately to be sent to various analog synthesizers ... There will be at least 10 of these sensor set ups. The idea was to keep it all analog, but maybe a bunch of sample and hold circuits could be interesting, once the sample rate is clocked with the square wave frequency and then phased correctly with the highs then I'd be getting pretty much exactly what I'm asking for huh ! - is there a way of achieving that with cheaper and/or analog components ?
  4. this might be interesting reading: http://www.electronics-lab.com/forum/index.php?topic=9124.msg52348#msg52348
  5. I remember asking the same thing here years ago ... Exactly the same issue - you have an output range from A to B and you want to scale it linearly so that A is now A1 and B is B1 A1 and B1 are within reason arbitrarily related to A and B - easy to do in code (with the possible resultant resolution drop), but harder to do with analog electronics Scaling (multiplying/dividing) is easy Adding voltage is easy Some sort of simultaneous equation involved with a circuit - but if I recall subtracting voltage is the hard part Say you wanted the signal ranging from A to B to equate to A-x to B-x -
  6. Hello, Question simplified: Say I had a 48Hz square wave whose high V value was modulated over time (see the black line in the first attached graphic) and I wanted to extract and output the curve of the modulation as a voltage (the red line)... How would I go about this ? Some thoughts that may or may not be helpful/relevant: The signal I am after is a low frequency signal compared to the one 'carrying it' (not to be confused with PWM!) - I thought that by simply adding a steep low pass filter I might be able to get way with it. But there is the worst case scenario to think about which is
  7. working now :) - So there is also a bit of work to do on the uP programming but I understand what is required (I'll need a 16bit I/O expander as well) - hmmm, so what are all those NOR gates doing like that ? I am yet to understand them ...
  8. I'd like to check it out but clicking on the pic or the text link below it pops up a window saying: You are not allowed to access this section Is there a paid subscriber function here ? I hope I'm not being rude asking if you could post the schematic elsewhere ? :-X thanks for your help! Nick
  9. Yep, thats definitely a start! What do you have in mind ? btw - the bottom limit off 100Hz is only because of the mechanical limits in the system thats its going to be finally impaled upon - it could go down to zero if need be, although the parts might not like that ! the odd frequencies I need i can sort the analog way using that voltage-freq chip I'll use for the ramping - hopefully a bit of nichrome wire will get things accurate enough with a adj Vreg and It'll stay that way with temperature etc... I'll have to see
  10. I was thinking yes I could enter Hz values into a uP and have a nifty LCD and telephone pad interface and let it do the math for me - but I'm still stuck with the same problem all along ... ok at one end in terms of resolution but then it all gets out of whack a the other end of the spectrum... Its because of the range I need, a factor of 10,000 (5 BCD values) - I'm hoping for 10,000 but maybe 1,000 is what I am stuck with because of pin counts on whatever I use It was suggested I look at this chip also http://www.st.com/stonline/books/pdf/docs/2086.pdf - which is neat in some respects but
  11. Just read your last reply - I'm understanding the 4059 a bit more now and should note that I meant the 4017 when i referred to the 4024 in my last post ... Like I said tho I'm still stuck with dividing periods rather than working directly with Hz - I want the value entered on the thumbwheel to be the frequency and not the frequency divisor. I'm getting an idea of how it works but this gear need to be used by other people who don't have the time to figure out the division, yes I know it only takes two secs... but the thing is I know that gear has been made that doesn't require it (just like
  12. Okidoki - I've found some BCD thumbwheels locally: http://www.jaycar.co.nz/productView.asp?ID=SR1250&CATID=&keywords=bcd+switch&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID= So each digit is represented in a 4 bit nibble (the unused reserved for Hex I'm assuming) - I have a couple of the little style hex ones you use a screwdriver on here to play with already until I want to buy the more expensive thumbwheel dec versions ... So, I have a nibble representing each of my desired decimal factors for
  13. Hi, I would like to build an device that provides a %50 cycle 0-5v square wave (easy!) - that has a range of frequencies that can be directly inputted from 100.0 Hz to 10,000.0 Hz (harder!) - I would like the 0.1 increments if possible ... I've played around with a microcontroller called the ooPIC but that always works in terms of setting the cycle period - because of this the frequency is always at the mercy of the resolution of the cycle period and I cannot achieve specification I outlined above... The device here: http://www.duallcamera.com/store/items/SpeedControls/MilliframeControlle
  14. The LDR cct is nice now, especially with the LPF on the input ... I have a problem with having too many projects on the go at once - I will move onto one before completing the last... The LDR cct has taken a back foot as it is not really required until the new year - the latest project is more mechanical in nature apart from the wireless modules I have purchased for it: http://www.maxstream.net/products/xbee/xbee-pro-oem-rf-module-zigbee.php These are the precious little static sensitive parts ... thanks for your info, always appreciated Nick
  15. Hi, I have never had problems with zapping components in digital ccts and have used a fair amount of different components that came in the static sensitive device bags... The other day two components arrived in the aforementioned bags and they are worth $32US each. I thought it would be a good idea to get a antistatic wrist band in this case... I'm not working on PC cases, just my own breadboard cct's and microcontrollers Question: Do I have to connect to the actual household earth (both cct and band) ? or is it ok to only connect to the ground of my battery powered DC circuit ? What a
  • Create New...