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  1. Closed: Re: Current rating for an 8 wire stepper motor with coils connected in series

    Thanks c_mitra.

    It was an 8 stepper with 4 coils each a DC resistance of 5 ohms. So with them connected in series there are two coils of 10 ohms each.

    It is a stepping motor so not sure if...
  2. Closed: Re: Current rating for an 8 wire stepper motor with coils connected in series

    Thanks Guys. Looks like there is no hard and fast rule. Can't find a datasheet so will work on the premise that if it is not too hot it is not too hot.
  3. Closed: Current rating for an 8 wire stepper motor with coils connected in series

    Hi. I have an 8 wire stepper motor which I have connected the coils in series to run off an A4988 driver.

    The rating on the back of the motor is 5V 1A

    I am driving it with a 20 volt supply. To...
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    [SOLVED]Closed: Suitable driver for a MOSFETs H Bridge

    Hi guys. I am sure this question has been asked before but when I search I get so many answers that don't really apply so I am confused.

    I have a 20V PSU which I want to power a 3 phase permanent...
  5. [SOLVED]Closed: Re: Connecting monitor speakers to a mobile phone

    Thank you Klaus. Those were the key words I needed.

    For anyone who is interested:
    - Use 2 core shielded cable for each channel.
    - at 3.5mm plug. connect i core to left (or right) signal and the...
  6. [SOLVED]Closed: Re: Connecting monitor speakers to a mobile phone

    OK then Klaus. Can I do that with something like a capacitor or will it need to be something more active?
  7. [SOLVED]Closed: Re: Connecting monitor speakers to a mobile phone

    Cheers Barry. Yes, they are powered speakers.

    Where should the shield connect to? The speaker GND or the 3.5 mm common?
  8. [SOLVED]Closed: Connecting monitor speakers to a mobile phone

    HI. I have just bought some second hand Phonic PS6 monitor speakers to connect to my phone.

    So I connected a 3.5 mm jack cable to 2 1/4" plugs for each speaker by taking the common and red wire...
  9. [SOLVED]Closed: Re: How to pulse a three coil stepper motor?

    Hi Klaus. Not sure what you mean.

    This is a three wire motor so at least two, possibly three, of the coils must have current going through them. Can't just energise 1.
  10. [SOLVED]Closed: How to pulse a three coil stepper motor?

    Hi. I have salvaged a three coil stepper motor and am a bit confused about how to pulse the coils to make it move. Here is a cross section image of the motor:...
  11. [SOLVED]Closed: Re: How reduce transient voltages with a transistor+zener+resistor regulato?

    Hi D. Thanks. I have seen capacitors in parallel circuits before but couldn't see the point.
  12. [SOLVED]Closed: Re: How reduce transient voltages with a transistor+zener+resistor regulato?

    Hi Brad. Yes I would if I was looking to do something practical from an interest perspective.

    But, I have no 40V clock signal. Be more straight forward if I have a clock to set it up to control...
  13. [SOLVED]Closed: Re: How reduce transient voltages with a transistor+zener+resistor regulato?

    Cheers Klaus. The heat is a big issue. And ugly. It is a compromise between simple and elegant. For the moment I will have a second small 12V PSU in the case. Simple and efficient. Still a bit ugly...
  14. [SOLVED]Closed: How reduce transient voltages with a transistor+zener+resistor regulato?

    Hi. I want to regulate a 45VDC unregulated power supply down to 300mA at ~12V. I was going to use a LM7812 until another member pointed out they have a max Vin of 35V. My plan was to use the circuit...
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    [SOLVED]Closed: Re: Is it possible to overload a MOSFET gate?

    Good point Gorgon. Thank you. I will probably use a transistor+zener instead. Not sure how this will cope with transients though. I will post that question in a new topic.

    - - - Updated - - -

    ...
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    [SOLVED]Closed: Re: Is it possible to overload a MOSFET gate?

    Cheers tony. A quick question about TVS diodes. The 1.5KE51CA diode you mentioned has a Minimum Breakdown Voltage of 48.5V and a Maximum Clamping Voltage of 70.1V. (which is the "maximum voltage drop...
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    [SOLVED]Closed: Re: Is it possible to overload a MOSFET gate?

    Here you go Klaus. Let me say that originally the circuit diagram was as shown in this new schematic, but when I increased the supply voltage, the opto coupler output promptly died, so I began...
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    [SOLVED]Closed: Re: Is it possible to overload a MOSFET gate?

    Thanks Klaus, well actually it is rather like Christmas tree lights... I will tidy it up and try again.

    - - - Updated - - -



    Maybe what? Too much power to dissipate? How would I know? It is...
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    [SOLVED]Closed: Is it possible to overload a MOSFET gate?

    Hi. I am using a RFP50N06 MOSFET to switch 24VDC into a DC motor which can draw up to 15 A. My test circuit was like this:
    http://obrazki.elektroda.pl/4707839900_1472547367_thumb.jpg

    And this...
  20. Closed: Re: Is it a good idea to use rectifier diodes in series to reduce a power supply volt

    Why would there be more heat dissipated dropping 0.6V over a rectifier and dropping the same voltage using a regulator? 0.6V @ 2A either way.

    By switch mode you mean a PWM setup. Right? That would...
  21. Closed: Re: Is it a good idea to use rectifier diodes in series to reduce a power supply volt

    Ooops. My mistake. It is a BD437. Thanks. But the same question still applies.
  22. Closed: Is it a good idea to use rectifier diodes in series to reduce a power supply voltage?

    Hi. I have a 12V PSU which I want to reduce to 4V 2A PSU. I have used a NPN power transistor (BD137) plus a 270Ω resistor and a 5V zener to make a regulator which gives me a 4.4V output which is...
  23. [SOLVED]Closed: Re: How to compare two bits in the same byte using ASM?

    Sorry Klaus, that is true. And Andre, it is a 16F88 as you guessed right.

    It takes perhaps 16 lines of code and speed is not really a factor.

    I was just looking for a tidier way of doing it....
  24. [SOLVED]Closed: How to compare two bits in the same byte using ASM?

    Hi. Is there a quick way to XOR two bits in a byte? If they are the same then do something else do something else.

    I can do this using btfsc and btfss but it takes many lines of code.

    Thanks.
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    [SOLVED]Closed: Re: Best way to switch 12V usin a PIC.

    Thanks Audioguru, you may be right as the BC547 has since died completely.

    Thanks Klaus. Makes sense. I will experiment.

    I take it from your suggestions that there should be no leakage...
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