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  1. (*steve*)

    transconductance amplifier

    :) Assuming you're somewhere near the place you mention to in your sig then the place is about 9150 miles from you. No, I haven't heard anything about them. As a moderator I have unique powers to look into the private lives of all participants. That, OR I posted in the wrong thread by...
  2. (*steve*)

    How do I see posted diagrams??

    Or worse, it's no longer there and lost forever :-(
  3. (*steve*)

    Can anyone ID this transformer?

    Assuming the 60mA is based on that rectifier combination, then using a full wave bridge rectifier into a capacitor should allow me to draw approx 36mA from the 700V DC (ref).
  4. (*steve*)

    transconductance amplifier

    The modules we build cost around £30. Maybe you should call in and build some :-) Are you using euro rack modules? Here is my synth:
  5. (*steve*)

    Can anyone ID this transformer?

    And the schematic for the other unit: I don't have a symbol for the tubes, but they're just big zeners, so that's OK. Note the -6.2V output. I rechecked and that;s the same on the other box... I got that part of the previous schematic wrong (I may update it later). I'm pleased that both...
  6. (*steve*)

    Can anyone ID this transformer?

    Here is the other unit:
  7. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    A colleague of mine used pre-sensitised board and laser printer output. Now he has built a machine to apply the resist film to the board directly. Be careful with the life of pre-sensitised board. Some has a very long shelf life, other stuff needs to be used quite quickly.
  8. (*steve*)

    Cursor mode on scope

    This particular model of scope is known for that feature.
  9. (*steve*)

    transconductance amplifier

    Are you building a modular synthesizer? My approach would be to ask Nathan (NLC). I've built a couple of dozen of his modules (mostly for the Zen of soldering) and he would probably be able to comment. From memory, at least some of his designs use an optocoupler based on a LED and a CdS cell...
  10. (*steve*)

    Can anyone ID this transformer?

    Nothing really exciting. I have some dekatron and some nixie tubes and I plan on making a clock. I plan on doing the division and digit driving using the dekatrons rather than logic. I could use a DC to DC converter to create the high voltage, but these transformers look a lot better :-)
  11. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    Read this. Note on slide 4: "etching always result in undercuts"
  12. (*steve*)

    Can anyone ID this transformer?

    No, just about the meaning of the DC spec. I'll reverse engineer the other box tomorrow. Same transformer, but significantly different circuit.
  13. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    Mathematics. Also toner transfer doesn't use an inkjet printer because inkjet printers don't use toner.
  14. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    You need to do more research. Toner transfer does not involve an inkjet printer. The laser method removes the resist from the board (I use high temperature paint) . The board is then chemically etched. etching removes exposed copper. As it removes copper some edges are exposed. These are...
  15. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    Yes, but the control, whilst sufficient for most normal tasks is not fine enough for ablating paint. I imagine you could use a tool with parallel cutting edges, but you couldn't do fine lines then (and it would be far too easy to snap)/ The areas already etched because it requires a far...
  16. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    If you're interested in what can be achieved, see here. The whole thread is about my many trials, and you might find stuff there of interest if you want to experiment (but you don't :-)).
  17. (*steve*)

    Best Low-Cost Home PCB Prototyping?

    Well... it's pretty hard to create an object less than three times the size of your error. So, if you want 0.5mm pads, you need positioning to be better than 0.2mm It depends on how much control you have over the laser. I gt the most accuracy and evenness of power per unit area by using the...
  18. (*steve*)

    Can anyone ID this transformer?

    Here is the reverse engineered schematic. I'm pretty sure it's accurate (it's not, see below). The device was last "checked" in 1990, and so was probably scrapped within 5 years of that (assuming a 5 year cycle for electrical safety checks which is about what I've seen in this environment)...
  19. (*steve*)

    Can anyone ID this transformer?

    Some photos of the simpler of the two units:
  20. (*steve*)

    Can anyone ID this transformer?

    It looks like a reverse engineering of the circuit may be in order. I have 2 of these from 2 different power supplies. I'll reverse engineer the simpler one first :-)
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