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  1. (*steve*)

    DMM allows current to pass but measures 0 mA

    You may have a damaged multimeter. Presumably it reads V and Ω correctly? How well does it work on its lowest voltage range? If you're really lucky there may be some overload protection other than the fuse which has failed short circuit.
  2. (*steve*)

    15W Laser Diode

    What current is being drawn from the 12V supply?
  3. (*steve*)

    Insufficient Power on my Load

    Excellent, then it will be a race to see which transistor fails first. Even in the current configuration both transistor are at mortal risk, but the BC558 has a somewhat unfair head start if the switch is open. Why not remove all the transistors and put the switch in series with the regulator?
  4. (*steve*)

    Nerve/Brain/Muscle spike sensing

    A colleague of mine (now sadly deceased) had a pacemaker which would talk via something like Bluetooth to a box attached to his computer. Every time he say down in front of his computer it would send a stored log of his heart activity to his cardiac specialist. One has to wonder if there's an...
  5. (*steve*)

    AC Measurement Question

    Well... It's not something I'd expect to see in a meter produced today. But it was not at all unusual in analog meters 40 to 50 years ago. And thanks for pointing out 2x rather than 1.4x.
  6. (*steve*)

    15W Laser Diode

    Here it is. I would like everyone who plays with high power lasers to read this at least twice (maybe once with each working eye). The following is only funny until you have damaged one eye.
  7. (*steve*)

    Car ECU think I found the fault?

    Yeah, and check that the leftmost trace hasn't been cut.
  8. (*steve*)

    Want to copy ultrasound tooth regeneration device.

    Ask on a medical or dental site.
  9. (*steve*)

    15W Laser Diode

    As a person trained as a laser safety officer... It's actually surprising what it is not illegal to do. However, if it is done in a workplace... The main consideration is safety. If you place others at risk then you are going to find yourself liable. This is clearly a class 4 device, and I...
  10. (*steve*)

    15W Laser Diode

    What current is being drawn from the 12V supply?
  11. (*steve*)

    AC Measurement Question

    I bet your meter simply has a diode in series for AC measurement Try reading the "AC" voltage of a battery. My prediction is that it reads 0V one way and 1.4 times the DC voltage the other way.
  12. (*steve*)

    Adcom 5400 amplifier blowing all fuses

    Google "dim bulb tester".
  13. (*steve*)

    Normal resistors for High Voltage application

    I would recommend that you work on low voltage stuff. You clearly don't understand what you're doing and we have no idea what is providing this high voltage. There is certainly the potential that you're trying to measure something that can kill you.
  14. (*steve*)

    Adcom 5400 amplifier blowing all fuses

    That's about a thousand times longer than needed :-( Unfortunately, only one side needs to be the right way around :-(
  15. (*steve*)

    Adcom 5400 amplifier blowing all fuses

    If it's a valve amplifier, you may be ok. But I guess it's solid state, right? It could be expensive to the point of it being uneconomic to repair.
  16. (*steve*)

    What are these sections of this power supply?

    Two of the tubes require 900mA, and the other two require 300mA for the heater. You'd be better off wiring the 900mA ones in series, and the 300mA ones in series and powering both of these pairs from 12V 1.5A transformer. *SNAP*
  17. (*steve*)

    What are these sections of this power supply?

    Because you need a minimum of 3.4A for the heater winding.
  18. (*steve*)

    What are these sections of this power supply?

    Here are some transformers that have almost exactly half the current required. You could purchase two of them.
  19. (*steve*)

    What are these sections of this power supply?

    You would typically buy one. However these days, transformers like that are not all that common.
  20. (*steve*)

    What are these sections of this power supply?

    Yeah, and the heaters require 2.4A, so the secondary must be rated at 3.4A or more
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