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  1. duke37

    Frequency response ?

    There was an article in RadCom a while ago describing how to send signals a long way. They used SHF and flat lenses intended to be used for rear view with caravans. The sending and receiving LEDS were the same. Alignment was achieved with visible light and several km were managed. Visible LEDs...
  2. duke37

    Receiving a radio signal...

    Most FM radios have a muting control to turn off the sound if no signal is being received. The gain of FM recievers is very high and if there is no signal then detected noise produces a rushing noise.
  3. duke37

    Can a low side driver control three N-type MOSFETs connected in series?

    If you are looking to switch high voltage and current eventually, you should look up the way that the France/England interconnector changes DC to AC.
  4. duke37

    Dual power supply

    If you get a dual 15V transformer, then the two windings need to be connected in series to give 30V at the ends and the connection will be used for 0V.
  5. duke37

    Dual power supply

    If the transformer is 10-0-10V then the best you can get on C1 is 14.1V less the diode volt drop. You want at least 18V on C1 to get 15V regulated output. Some voltage measurements are required. A small capacitor close to the input of the 7815 is recommended.
  6. duke37

    Magnet pole pieces...

    My guess is that the field will be strongest at the magnet and will be weaker as you move along the pole pieces. The lines of force appear to have a tension so will concentrate near the magnet and be much weaker at C/C.
  7. duke37

    Can I pour 99% isopropyl alcohol onto my light socket contacts? Safe?

    I knew a chap who emptied a petrol tank and then stream cleaned it. When he tried to weld it, there was a collosal bang and the tank shot across the garage. Putting any liquid in which can generate an explsive atmosphere is not to be advised. I have not looked at any photos which have not been...
  8. duke37

    Is my setup 'earthed'? I live in Canada and have a UK machine.

    But you have not posted links or photos of what you want to power. The UK supply is 230V +10% -6% i.e. 216.2V to 253V at 50Hz. My supply normally sits about 240V which was the old standard. You should be able to get something close in Canada. The Canadian 60Hz should not be a problem unless the...
  9. duke37

    Saft Power Systems PSU problems

    Some details of the device it is used with would help, including pictures. High voltages in alternators could be due to excessive speed. If the module is shaft mounted, how do you measure the voltage?
  10. duke37

    Can I pour 99% isopropyl alcohol onto my light socket contacts? Safe?

    My Oxford pocket dictionary says inflammable means "easily set on fire or excited". Flammable = inflammable. Either way, putting in a container which is liable to spark is not to be advised.
  11. duke37

    Is my setup 'earthed'? I live in Canada and have a UK machine.

    You must have an earth for this appliance, A regulated supply should not be necessary unless you are in the sticks. To get an earth you MUST have three terminals. Adaptors to supply anerican devices from UK sockets are avalable in the UK. Presumably the opposite way round is available in...
  12. duke37

    Can I pour 99% isopropyl alcohol onto my light socket contacts? Safe?

    A petroleum product such as white spirit is better at removing grease than alcohol. Take note that many solvents are inflamable and water is conductive.
  13. duke37

    Confusing about grounding for regular AC-DC SMPS

    I mis-read the diagram. The supply to my house is PME which I think is phase, multiple earth where the 11kV transformer and all properties have the neutral conncted to earth. There was a fault in my father's house where the neutral was connected to the earth. This worked until sunday dinner was...
  14. duke37

    Confusing about grounding for regular AC-DC SMPS

    Connecting neutral to earth is not permitted in the UK. If it does occur due to a fault, then a trip will actuate as sonn as there is a slight current, typically 30mA, running between them. What country has this system?
  15. duke37

    Treadmill Console Button Panel Ribbon Cable Fail

    Do not go near it with steel wool. One little loose strand could be disastrous.
  16. duke37

    Frigidaire CFMV164LSA over-the-range microwave capacitor location

    I think it is an alkali such as sodium hydroxide which will react with aluminium to produce hydrogen not acid. Grease could be cleaned off with white spirit or paraffin and then washed well.
  17. duke37

    Trying to understand PWM / solve relay buzz

    BobK has shown up my faulty logic and a simple diode will not do. Relays or transfomers can buzz for years without trouble. I have encountered relays in old electric fencers which switch about once a second and these fail because the end stops get worn down and the relay then sticks in. A bit...
  18. duke37

    Trying to understand PWM / solve relay buzz

    I would replace the capacitor with a diode, the relay inductance then is used to give a fairly steady current with little buzz. The diode is smaller, lighter and cheaper than a capacitor. Even better would be to use a FET instead of a relay to drive the LED. A small capacitor woud be needed...
  19. duke37

    Sherwood Power Amp Crossover Distortion

    I do not think that the difference in the gate/source voltage is important. It will affect the static output voltage but you should be able to adjust this to zero. Any silicon diode will do, IN4148 or 1N4007. Rather than a string of diodes you could use a zener or has been suggested a resistor...
  20. duke37

    Sherwood Power Amp Crossover Distortion

    There is a diode D107R? which I think controls the voltage between the gates of the output transistors. You could try another diode in series to raise this voltage but check dissipation.
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