Search results

Search Forums New Posts
  1. (*steve*)

    Floating pins on Microcontroller

    With the picaxe there is a potential problem with the serial input pin floating. A stray voltage here could place the picaxe into programming mode See here. Never, ever, leave the serial input pin of the PICAXE chip floating (unconnected). The 'serial in' download pin is shown in the pinout...
  2. (*steve*)

    Charging/Discharging circuit for multiple 18650 batteries

    I was thinking about the cheap charger modules. If the cells are in series you need to disconnect them to charge them this way. If they are in parallel you only need a single charger module. No, if you have your cells (not batteries) in parallel, a single charger module can charge them both...
  3. (*steve*)

    Was I dreaming (fast PCB etching)

    I'm not sure I was dreaming or if I read it... Did someone post or provide a link to a method they used to etch PCBs quickly? It involved electroplating the copper off the board then finishing the process in conventional chemistry. Or did I just dream it?
  4. (*steve*)

    Charging/Discharging circuit for multiple 18650 batteries

    Most chargers just have a single led. If you need a display of charge level you can either but one separately or build one yourself. Do you know what varies with charge level? I'm also concerned that you don't know the difference between a buck and a boost converter.
  5. (*steve*)

    Calculate radius of a copper wire

    Currently you've gone one step too far. You want the equation describing the resistance in terms of the wire's diameter and length. Also, given the power and current, can you calculate resistance? Putting these together you'll have an equation with 2 unknowns. Do you have sufficient...
  6. (*steve*)

    Li-Ion battery question

    This link may help you. There are many modes of failure. http://www.mpoweruk.com/lithium_failures.htm
  7. (*steve*)

    Looking for a one cell lcd display (or something else) to use as a light diode

    Do these devices use any power anyway (other than for switching)? How long would the charge on a capacitor hold these "open" and would this be sufficient for your needs?
  8. (*steve*)

    Newbie Project

    One solution is to monitor the power to the printer. It probably draws more current as it prints. A fairly simple circuit could detect this and sound an alert. On the network you could sniff packets and sound an alarm when significant traffic is designed for the printer. The drawback here is...
  9. (*steve*)

    Driving this MOSFET with PIC

    But since you won't show us the circuit, we can only make assumptions about it. I'm assuming it is wired sensibly. Also, I think you fail to understand the voltage/current behaviour in an inductor. Or perhaps you fail to understand saturation. Whatever it is, you also fail to be able to give...
  10. (*steve*)

    Wayne Kerr 7010 manual

    You are an absolute legend!
  11. (*steve*)

    Need help repair Sunshine ATX psu

    It's difficult. You've dome the right thing to try to load the power supply though. let's see if @HellasTechn comes up with anything. BTW, the 23.4V looks fine. The datasheet specifies a max of 42V, and a sensible range of 10V to 40V.
  12. (*steve*)

    Project Kickoff - Variable Frequency Generator WITH interrupts (gaps)

    For a 1.5kHz signal, you create an interrupt at twice this frequency. At each interrupt you tougher the output state except when you calculate you're at the missing tooth. At this point you just ignore 2 interrupts. By changing the interrupt frequency you will be able to alter the stimulated...
  13. (*steve*)

    Capacitor charging

    Amusingly enough those electronic fly swats are illegal to import into Australia. I'm not sure why. Maybe the flies have a good lobbyist.
  14. (*steve*)

    Driving this MOSFET with PIC

    With any normal circuit this will not be a consideration.
  15. (*steve*)

    Help with 1970's TV!!

    Get an old set top box with an old school analog modulated output
  16. (*steve*)

    Driving this MOSFET with PIC

    What is the turns ratio, and what is the peak voltage you expect to see on the secondary winding? If the answers are 500 and 12000, the expected peak on the primary is 24V.
  17. (*steve*)

    Wayne Kerr 7010 manual

    Has anyone used one of these? I acquired two of these devices for almost nothing. Both appear to work and I am able to measure various resistances, capacitance and inductances. However I'm sure the equipment can do far more than what I do with basically one button! I have searched the web...
  18. (*steve*)

    MOSFET Sub-Nanosecond Switching

    Those devices I read about were diodes. IMPATT and TRAPATT. The book is 1982 vintage, so there are doubtless newer devices. It's always interesting how diodes can provide gain. These things have picosecond switching times. Kinda like tunnel diodes and step recovery diodes.
  19. (*steve*)

    Driving this MOSFET with PIC

    Unless he is planning for a 2MV pulse on the secondary!
  20. (*steve*)

    Common Cathode Triple digit display pinmap help!!!

    It wasn't a silly question. You just didn't know the easy way to do it. By the way, I use my multimeter on the diode test range to figure out the connections. With a bit of practice, the longest part is writing down what each pin does. Good to hear you have the LCD driving stuff figured out too.
Top