Search results

Search Forums New Posts
  1. (*steve*)

    1n4007 is getting hot

    Can you post a photo of them with a ruler or something beside them for scale. Also, if you can measure the voltage drop across them at some known current, it would help confirm what's been said earlier.
  2. (*steve*)

    Connecting LED Array to a microController?

    No problems. What experience with larger electronics do you have?
  3. (*steve*)

    Boolean expressions simplification

    How much have to figured out yourself, and where are you stuck? In the first question, in part, you have ABC + A'BC. Can you simplify that?
  4. (*steve*)

    Connecting LED Array to a microController?

    The microcontroller can't directly drive that array. You should have the microcontroller drive a transistor which will switch a relay. You could also control it via a MOSFET (a type of transistor) but you would require a common connection between the Arduino power supply and that of the it...
  5. (*steve*)

    Non invasive current monitor

    As a side note, you can't measure anything without having an effect on it. (Heisenberg was right). Even these ACS712 chips add some series resistance and inductance. Practically speaking though, there would be very few cases where it could be noticed.
  6. (*steve*)

    What cap, what resistor?

    Did you watch the video?
  7. (*steve*)

    What cap, what resistor?

    If you have weak pull up on P0, or if it sources leakage current, you'll slowly charge the capacitor. The circuit you have would need to use a very small value of capacitor because the piezo sensor cannot generate a significant current.
  8. (*steve*)

    What cap, what resistor?

    You should probably use a proper peak and hold circuit. See here.
  9. (*steve*)

    Solar charging a LiFePO4 Battery (advice welcome!)

    OK, in that case it is probably current limited voltage source. If you have a multimeter, the voltage across the output terminals when disconnected should be the maximum charge voltage for the battery. That's generally 3.6V per cell for LiFePO4, so I expect your battery has 4 sets of cells in...
  10. (*steve*)

    Solar charging a LiFePO4 Battery (advice welcome!)

    Yeah, but I don't know what that is either. Does it just connect to 2 terminals on the battery, or does it have a special multi-way connector?
  11. (*steve*)

    Battery help!!!

    No, it's a single LiPo cell.
  12. (*steve*)

    Battery help!!!

    Measure the size of the original battery and/or the size of the space it has to fit into. Then find one with the same voltage (what's the bet it's labelled as 3.7V) that will fit into the space available. I had to do this for a device that had the battery fail. Unfortunately I had to get a...
  13. (*steve*)

    mosfet power supply issue

    All of them except for those with 4 wires. (Not that you'd want to use a dual gate mosfet here)
  14. (*steve*)

    Trying To Modify A Radio

    Do I need to add the "WOO WOO" tag to this thread?
  15. (*steve*)

    Solar charging a LiFePO4 Battery (advice welcome!)

    Lithium batteries require chargers which handle the balancing of cells (or at least to prevent overcharging of cells) I'm not sure how or where the battery management is done (presumably in the charger, but I'm not sure - given that it's a lead acid replacement and is charged by a lead acid...
  16. (*steve*)

    Anyone created a database to cross reference schematics, articles, etc?

    The real answer is full text searching of the articles. If you want to photograph each page, then do an image to text conversion of each article (each page may be sufficient), then load the text into some full text searching engine it should do the trick. There image to text can be done very...
  17. (*steve*)

    Ball wall target board

    It acts like a low value resistance when turned on, rather than having a small voltage drop across it. This means the capacitor will be more completely discharged.
  18. (*steve*)

    Health Care is so damn expensive...

    My wife has just come home from her 5th trip to hospital this year (or something like that). She had a 4 day stay after some further surgery (no ICU this time) and the whole thing cost us $25 (which we were asked to pay up-front). Very nice private hospital. She is now on first-name terms...
  19. (*steve*)

    Ball wall target board

    You're probably better off with Q1 being a mosfet
  20. (*steve*)

    Window comparator help (Battery monitor)

    OK, here's a circuit. U1 is a S-1000N36-M5T1U available from Digikey for under $1. U2/U3 are halves of a SN74LVC2G14DBVRG4 available from Digikey for under 50c. The other components are non-critical. LED L1 flashes at about 1.2Hz when the voltage detector triggers (under 3.6V) Reduce C1...
Top