Search results

Search Forums New Posts
  1. (*steve*)

    Partialy Discharging Capacitor

    It's a light sensor with variable sensitivity. It essentially integrates the light over time and triggers the rest of the circuit to stop the flash once sufficient energy has been "seen" by the sensor.
  2. (*steve*)

    Consultation

    But it says it generates 60V?!
  3. (*steve*)

    Need advice on how to control commercial HVAC unit just past electronic timer control

    Yeah, you would want to use a contractor and have that installed by an electrician. You can then use a rpi too switch the contractor. If the contractor requires AC, it is probably best to used the rpi to control the relay and have the relay switch per to the contractor.
  4. (*steve*)

    Slider pots

    The 50KA almost certainly means that the maximum resistance is 50kΩ and that it is a logarithmic (or audio) taper. Everything else about the pot is likely to be related to mounting and track length etc. Just find one that fits. You could look on rs's web site http://uk.rs-online.con
  5. (*steve*)

    Partialy Discharging Capacitor

    There are schematics of some flash units on the web. Search for the schematic of a Metz 45ct1. I'm still not sure how they work :-)
  6. (*steve*)

    Vintage transistor tester?

    Me too. I thought the eBay auction was long finished (or did you find a new one?)
  7. (*steve*)

    Partialy Discharging Capacitor

    The answer I have about the discharging of the cap was based on your original question which did not have any context. Flash tubes are NOT controlled by varying the input voltage, and pwm is used in the most modern of flash units not to reduce intensity, but to increase the duration of the...
  8. (*steve*)

    741 op-amp

    There AD797 will blow it out of the water. But be careful reading the specs. That -120dB will be for the most favorable set of parameters. For example, unless otherwise specified, it will be for a gain of 1 and it will rise for higher gain.
  9. (*steve*)

    741 op-amp

    There is no simple answer. It will depend on the signal level, the gain, the power supply voltage, and a plethora of other factors. It is reasonable to say though, that the venerable 741 is by no means low noise or low distortion by today's standards.
  10. (*steve*)

    Burleigh WA-20 Wavemeter

    Some time ago I bought a very cheap Burleigh high voltage DC op-amp PZ-70 thinking that I could probably find a manual somewhere. Alas, trying to find *and* information on Burleigh equipment has proven impossible. I suspect you may be in the same place as me. Having said that, maybe this is...
  11. (*steve*)

    Stupidly Simple Question

    Thanks for the quick reply. Yes it was in jest. The mains connector is reasonably common, but not so frequently used these days. It is coloquially known as a figure-8 plug, out more exactly as an IEC-C7 connector. The DC connector is not a barrel connector and I can't easily recognise it.
  12. (*steve*)

    Video with face recognition

    What you are looking for is technically termed "a miracle". In cameras it is done using a very powerful image processing chip. The chance of getting your hands on one with enough documentation to use it are possibly also in the realm of miracles.
  13. (*steve*)

    File indexing on a web server

    Is your server running on a Linux server? Is it your server? If so, I would write a script which hard links the files into one of 27 directories (a to z and other). Then you can simply point your server at the top level directory and let it handle it. If you put a file index. HTML in the "I"...
  14. (*steve*)

    Stupidly Simple Question

    It would be useful if you could post a sharp picture showing the power sockets. The are a couple of options for the mains input, but if you've been alive in the 21st century and can't recognise it, then maybe it's something obscure. The 12V socket is most likely a barrel connector of some...
  15. (*steve*)

    Shmoo Plot

    In practice, I believe it is normally done by quenching the flash prior to complete discharge of the capacitor. I'm not sure exactly how that is achieved since the discharge current in very small camera flash units can be between 50 and 100A.
  16. (*steve*)

    Shmoo Plot

    Au contraire, it is exactly what Harald suggested. Presumably you have results in all of these cells. All you need to do is to derive a method which returns one value for success and another for failure. Harald suggested doing that with conditional formatting, your example appears to use an...
  17. (*steve*)

    Partialy Discharging Capacitor

    It depends on what you mean by "discharge xx%". However if you can restate that as "discharge to xx Volts" then the answer may be as simple as using a suitable value resistor in series with a zener diode. For example, if the capacitor is charged to 300V and you wish to discharge it to 200V...
  18. (*steve*)

    Circuit Issue Help

    It's good to make the mistakes early on. You'll never forget then and you'll know what to look for.
  19. (*steve*)

    Gold-coloured areas on laptop circuit boards - gold or pyrite?

    There might be enough gold there to buy a mouse a burger (a very small burger) AAAAGH autocorrect
  20. (*steve*)

    Circuit Issue Help

    It will work if you don't have the LED. The load from the LED is too great for the output to maintain a valid output logic level.
Top