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  1. (*steve*)

    torque question

    In real life things can get more complex. At 45 degrees to need to ensure you don't lose grip. If that power can hold you still, it won't get you moving. If you're already moving and can trade speed for height, your kinetic energy can be traded for potential energy going up the slope, with...
  2. (*steve*)

    Transistor Power

    The source you should be using is the datasheet. This may just list the basic specifications or it may have a long series of tables, graphs, and even application circuits. If your device is a power BJT, you will likely find an SOA graph (safe operating area). This typically looks like a...
  3. (*steve*)

    Multiple mosfet driving

    Can you satisfy our curiosity by telling us the part number of the MOSFETs and if possible the supply voltage to the emitter follower and it's emitter resistor value. It should be relatively straightforward to calculate the switching losses
  4. (*steve*)

    Li ion Battery charge and use circuit

    It is perfectly OK. Depending on the load current vs the charge current, you will either discharge the battery slowly or charge it slowly. Your charge current must be limited and the voltage be no higher than the fully charged battery voltage
  5. (*steve*)

    Cheap Motion sensors , chinese I think

    R14 and C15 look to be the ones. Looks like you were on the right track. Can you measure either/both of the original values?
  6. (*steve*)

    Cheap Motion sensors , chinese I think

    Nope, still getting the same message. I'm approximately half way between Beijing and the Ronne ice shelf. I find that search engines differ greatly in their utility. In my experience Google is more consistently reliable in finding datasheets (and I look for them a LOT) Now you have the...
  7. (*steve*)

    Cheap Motion sensors , chinese I think

    Yes, I'm sooooo far from Australia :-P
  8. (*steve*)

    Basic Soldering advice

    When I've taught SMD soldering, I always start with really thick solder (3mm) and large tips on the soldering iron. When you start soldering 0.5mm pitch or 0402 (and smaller), even your smallest tip and finest solder seem huge. I've never found the need for extra flux in the stuff I've done.
  9. (*steve*)

    Multiple mosfet driving

    10k gate resistors? Are you sure? Could they be 10Ω? If they're really 10k then you should be able to drive more gates from the same source. This would also imply that the switching speed is very slow and this switching is infrequent.
  10. (*steve*)

    Basic Soldering advice

    Some fluxes DO clean the metal. These are exactly the sort that you need to avoid using for electronic work. Note that some electronic fluxes are so active at grabbing oxygen that they can strip it from copper. This could be argued as a cleaning process but it is specific to oxidation.
  11. (*steve*)

    Cheap Motion sensors , chinese I think

    Thanks. If only we knew earlier... The datasheet in question is available in English (it's also the first hit on Google when you search by the part number) Here (thanks to Lady Ada) Edit: it's hard to post links from Google that work consistently. Here is the file:
  12. (*steve*)

    Basic Soldering advice

    Totally off topic, but this is interesting because, as I understand it, drug offences exist at both the state and federal level. Whilst a state can remove its own laws, or decide to simply not enforce them, only the latter option exists for federal laws (assuming the decriminalization if at a...
  13. (*steve*)

    Old Silicon Chip Magazine project. Solar/Wind controller

    You could also write to Silicon Chip and ask them. They get enquiries like this and publish them along with their suggestions. I subscribe to silicon chip, so if you do this and don't have access to the magazine (and they don't reply directly to you) I could pass along their answer.
  14. (*steve*)

    Cheap Motion sensors , chinese I think

    Sure, I'm lying. Perhaps you can tell us the part number of the IC?
  15. (*steve*)

    HP 54510A Power Supply Smelling

    I'm still inclined to think that it may be due to excessive ripple on the power rails, but that may be because I'm not greatly familiar with the protection circuit. Having the protection circuit disabled isn't the end of the world. I wouldn't leave it on when unattended, and beware that a...
  16. (*steve*)

    HP 54510A Power Supply Smelling

    In that case the problem is not just that the SCR is dead. The fault may be in the protection circuit.
  17. (*steve*)

    Cheap Motion sensors , chinese I think

    If the link worked, I would have... Is it this?
  18. (*steve*)

    HP 54510A Power Supply Smelling

    Here is the datasheet on that SCR. Remove that SCR completely and measure the resistance between all combinations of all three leads (there should be 6 measurements. Do this on the diode test range on your meter. the 6 tests are red on pin 1, and black on pin 2, then 3 (2 tests). red on pin...
  19. (*steve*)

    Cheap Motion sensors , chinese I think

    14 pins? If so, it's probably a quad op-amp. The output of the sensor is the difference between the signals from 2 IR sensors. It quite likely has 2 stages of amplification, a threshold detector and a pulse extender. If it's a 16 pin device, it may be an M7616P, a dedicated PIR chip. edit...
  20. (*steve*)

    HP 54510A Power Supply Smelling

    Sorry about the delay getting back to you. Did you disconnect the SCR or the connection from the protection circuit to it? Is there still any clicking? Can you get a picture of the SCR? I don't imagine it's overly critical.
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