Search results

Search Forums New Posts
  1. duke37

    Capacitor charging

    To make a transformer with a greater turns ratio, you could add more turns on the outside of the transformer you have. The new winding should be in series with the existing secondary and connected in the correct phase. If you have an inductance meter, add turns to equal the inductance of the...
  2. duke37

    Capacitor charging

    If you show a schematic as previously requested we might be able to help. There could be two possibilities 1. The invertor cannot supply the voltage. Higher voltage components may be required. 2. The invertor cannot supply the leakage current of the high voltage capacitor. Try a disc ceramic...
  3. duke37

    Connect a 2 coil stator to 3 phase ESC possible?

    That's better. I cannot work out how the motor works, it seems to have a non contacting magnetic 'commutator' to energise the rotor. There must be another magnet somewhere either electro or permanent to react with this field. A simple radial fan will work in either direction but it is much...
  4. duke37

    Connect a 2 coil stator to 3 phase ESC possible?

    Still cannot see the picture, my computer says there is a security problem. Why not just attach the picture?
  5. duke37

    Connect a 2 coil stator to 3 phase ESC possible?

    If the motor is two phase, then the windings are at 90 deg. A three phase controller will need windings at 60 deg. The drive is AC and diodes will mess this up. I do not see your picture.
  6. duke37

    Simple 12v 3amp power supply

    To change AC to DC you need a rectifier. The best solution is to use a bridge which can be made from four diodes or a bridge rectifier which is a square block with four connections, two for AC and positive a negative output. You may need a heat sink if running at the full 3A. To limit the...
  7. duke37

    Simple 12v 3amp power supply

    Just connect to the transformer output. You will get 12V AC at up to 3A, the maximum power will be 12*3 = 36W. What will be using the power?
  8. duke37

    Potentiometer only kicks-in in for the last 10% of the turn (guitar effects pedal)

    Q2, Q3 and Q4 are identical amplifiers which seem to be more complicated than necessary. Q3 and Q4 clip the signal when it is large enough. The sustain pot alters the gain to push the signal up into limiting. The gain of Q4 can be raised a little by bypassing R22 with an electrolytic capacitor...
  9. duke37

    Potentiometer only kicks-in in for the last 10% of the turn (guitar effects pedal)

    I see the board and component positions but do not see the schematic. It appears that the pot is OK but it will be necessary to detgermine the effect of the pot in the circuit and if there is a critical threshold.
  10. duke37

    Magneto Resistor Supplier

    Welcome to the forum. Please give more details of what you want. What is the magneto maker and what is it used in? A picure of what you want would be a big help.
  11. duke37

    I need a relay or something

    Just use a mosfet with the gate driven by the brake signal. It should have a capability of 10A or so. The gate should be connected via a resistor, say 10k to 100k and a pair of diodes to restrict the gate to between 0V and 12V.
  12. duke37

    Reed switch

    You should use a low power reed relay and use a transistor as a switch. The transistor should be capable of 1A and the base should be driven by a current of about 20 to 50mA. If you use a fet, the gate should be raised to 12V to turn it on and a resistor to earth to turn it off.
  13. duke37

    Looking for a transformer for my new video doorbells

    A fuse is always a good thing. It depends on the load as to whether 1 amp will be enough. A bell may take much larger peak currents than the average.
  14. duke37

    Looking for a transformer for my new video doorbells

    The original transformer may not be able to provide enough current with the two bells but is unlikely to be damaged if current is drawn for only a second or so. The 40VA transformer will be plenty strong enough for the job so you can use it.
  15. duke37

    Half bridge inverter

    The diodes as shown do not restrict the drain voltage which can be very high due to the inductive load. Snubbers are often used to restrict the peak voltage. This is not my area of expertise.
  16. duke37

    Successfully unsoldering a big relay

    If you use the method of a wide soldering bit heating all contacts together, then do not suck the solder away. In fact, it may be better to add a little solder so that all contacts can be melted at the same time. What is wrong with the relay? It may be possible to change the contacts 'in situ'.
  17. duke37

    Successfully unsoldering a big relay

    Is that a big relay? Looks like a standard size to me. I have used a solder sucker to take a lot of the solder away and then remove the rest with braid. If you do not have braid, then the outer screen of co-ax cable can be used. The thinner the wire the better so that capilarity attraction is...
  18. duke37

    Any ideas - Rotary momentary switch?

    One way, perhaps a bit inconvenient, is to place some reed relays inside the cabinet and use a hand held magnet to activate them. Are you going to get the old radio working, at least for the sound output?
  19. duke37

    How can i add a trigger to this circuit to make it not electrocute the user?

    This is more difficult. I would use a piece of wooden dowelling or broom stick. I have the facilities to slit the dowel down and cut a groove in one side, then glue back together. Long drills are available but are expensive and difficult to hold to run down the center. How far are you from...
  20. duke37

    How can i add a trigger to this circuit to make it not electrocute the user?

    Any stiff wire will do. A clothes hanger will provide what you want. For a longer length, galvanised steel fencing wire is available. Try a local farmer for an offcut.
Top