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  1. WHONOES

    Good rosin flux paste brands?

    Don't know about the brand you mention, but I just use a rosin flux suspended in alcohol if I need to flux a joint if the rosin cored solder is not up to the job. As I have said elsewhere I would never use an acid based flux on a pcb or any electrical joint for that matter.
  2. WHONOES

    Good rosin flux paste brands?

    I am retired now so haven't done any SMD for a while but I used to dab a pad (just one) with a drop of flux, tin the soldering iron and dab it in turn on the same pad. Now place the component on the pads and touch the tinned pad with you iron. For the other connection, a dab of flux then touch...
  3. WHONOES

    Intermittent audio from speakers

    Unlikely unless it is a very common part. Have a look on the case, it may have a part number that could be traceable. If not you will have to find a suitable replacement that could be hard wired in.
  4. WHONOES

    Phantom powered preamp

    Had a quick play last night. Came up with the circuit attached. It is single ended and has (in simulation) a 10MHz bandwidth. If that is to much you could put a miller capacitor round the FET. Distortion for 17mV Pk - Pk is less than 0.001% at a gain of just over 10dB. If it is a bit too...
  5. WHONOES

    Phantom powered preamp

    Be interested to know what you come up with.
  6. WHONOES

    For Sale: ZV-Z235 Rohde & Schwarz Calibration Kit

    Didn't know this was a sales forum.
  7. WHONOES

    Wire spool - what is it worth?

    Probably a few of dollars a Metre / Yard if you sell it piecemeal. Put it on Ebay and see what sort of response you get. It is after all only worth what people are prepared to pay.
  8. WHONOES

    Phantom powered preamp

    I think the NE5534 with the phantom 0V is the simplest.
  9. WHONOES

    Intermittent audio from speakers

    Sounds as if the relay contacts a little burnt. If you can get the cover off then, you could clean them with a very fine abrasive paper. If not then you'll probably have to replace it.
  10. WHONOES

    Phantom powered preamp

    Why not use a low power opamp? To get rid of the excess PSU volts you could put a low current zener in series with the opamp supply lead and then bypass the amp with some 10μF and 100nf capacitors. I have done similar and it works OK.
  11. WHONOES

    Long input activated circuit

    Yup. You could use a 555 for the timer. Or you could do the whole lot with a bunch of Schmitt nand gates as in the 4093 that AK recommends.
  12. WHONOES

    Long input activated circuit

    You could use the output of your circuit to trigger a timer and then logically and them together then if the sound is still present when the timer terminates, the system will trigger.
  13. WHONOES

    Creating A Half Wave Motor Controller

    If you were to go down the DC and PWM path, you could control the speed using a tacho connected to the shaft of your motor and use its output to vary the pulse width of the controller. A small DC motor could be used as the tacho.
  14. WHONOES

    Laser for welding small plastic pieces?

    If you have a particular problem gluing certain plastics, try contacting a manufacturer like Loctite for a solution. In my experience they are very helpful (they want you to buy their product after all). Some years ago I had a problem trying to glue some acrylic parts, in a production...
  15. WHONOES

    Current source for a Capacimeter

    I agree with Steve. I have used the circuits shown in 3.1 and 3.4 hundreds of times down the years. They both work well.
  16. WHONOES

    Good rosin flux paste brands?

    I generally use a rosin based flux suspended in alcohol. It is easy to apply with a small artists brush. I will never use an acid based flux on electrical connections particularly PCB's. If you don't completely remove it or neutralise it, it will nibble away at your components / connections. I...
  17. WHONOES

    Good rosin flux paste brands?

    Why do you want a paste. Are you planning to use it as a tip cleaner?
  18. WHONOES

    How to make a day/night cycle controller

    You could use a 5V wall wart rated at 1A and put a 68Ω to 75Ω resistor in series with each LED and the connect them all in parallel. Through types will make the job easier. 20 LED's running at 20mA each will consume about 400mA.
  19. WHONOES

    Converting US/EU to UK plug

    If it is made for the US market it will be designed to run at 110 to 115V so will not be suitable for the UK. A model suitable for the EU would be OK and as you surmise, you could replace the plug with the superior UK type. They are not usually earthed as there no external metallic parts that...
  20. WHONOES

    Securing LED to heat sink?

    Drill and Tap fixing holes of an appropriate size. If the holes are 3mm dia then drill and tap for M2.5 or M2. It's not difficult. Just remember to remove any burr you create.
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