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  1. E

    Convert +12V DC to -30V DC

    search for "Boost Converter"
  2. E

    PSU Using The LM338

    Hi The LM338 can drop as much a 2.5-3v across it. Plus 2v for rectifier..so maybe an 18v transformer output would be better.
  3. E

    Apple vs the FBI

    so after you read the encrypted data..,what will you do with it?
  4. E

    LTSpice "High-Z" output

    Hi Those are static params that are read before a simulation run. Instead, use a switch contact in series with the gate output. Control the switch with "enable" pin.
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    Why drop in voltage in this circuit ?

    Move the buzzer to the collector side of Q1. 20V supply is a little odd though. Also, add a diode across the coil of the buzzer
  6. E

    Battery monitor indicator ??

    Can you not invert the output of the LM3914 to the 22.5v LED in the same way as shown in post #1 There would still be less components than post #1.
  7. E

    Battery monitor indicator ??

    Hi The easiest way to do this would be using an LM3914. But the LEDs would need to light in linear increments. Your power supply is 26v. LEDs would light like this: 25.5 24.5 23.5 22.5 21.5 20.5 ....... ..... ... Is that OK?
  8. E

    Battery monitor indicator ??

    Hi Just use an LM3914 and divide the input voltage down to provide the appropriate scaling.
  9. E

    Hall sensor A1122LUA-T resistance

    If VCC is 5v, and interfacing to 5v TTL device input, just connect a pull up resistor (2.2k - 4.7k) from VCC to Vout, then connect Vout to device.
  10. E

    Hall sensor A1122LUA-T resistance

    Hi Quote from datasheet. " After turn-on, the output voltage is VOUT(SAT) . The output transistor is capable of sinking current up to the short circuit current limit, IOM, which is a minimum of 30 mA". That basically means 30ma load is a short circuit. What is the Vout pin going to connect to?.
  11. E

    Battery Monitor

    Hi So using an LM3914... What is the power supply voltage? What is the LED specification? What is the voltage range you want to monitor? With ten 1v steps and 24v max, range would be 15-24v. Is that what you want?
  12. E

    Problems with Royer oscillator and an aircore transformer

    Post an image of the complete schematic..
  13. E

    Single Digit Seven Segment Display Scoreboard HELP!!

    Hi 1. Make sure Lamp each test pin is connected to ground if not used. 2. Connect a 1uf, 25v, cap from +5 to pin 15 of 4033. This will make sure the 4033 resets on power up. Do this for each 4033 but you can test it on one of them. So pin 15 of each 4033 should be like this: +5v | C=1uF...
  14. E

    Single Digit Seven Segment Display Scoreboard HELP!!

    Hi. Its a little difficult to identify each of the chips. I've uploaded part of the photo you sent that marks the two sections of the breadboards 1 and 2. Use these and the letter/number markings on the breadboard to "call out" specific wire connections. For example, the first breadboard hole...
  15. E

    How do I figure out these resistors?

    Basically, you need to know: Base input voltage Relay drive current Gain of transistor Hi.. Example: Vb = 9v <--base input voltage (same as (Vcc) supply voltage) Ic = 236mA <--Collector current (current to drive relay = 9v/38 = 236mA (estimate)) hfe = 100 <--Transistor Gain = 100 Vbe = 0.7v...
  16. E

    Single Digit Seven Segment Display Scoreboard HELP!!

    Ok...the displays shouldn't light on power up if pin 14 is grounded. That's good. But we still have to find out why the button doesn't increment the display. Yes, but you fixed it by grounding pin 14. That's good. What I was looking for was an alternate circuit path that may have been...
  17. E

    Single Digit Seven Segment Display Scoreboard HELP!!

    Hi If displaying 8, verify that LT is not enabled. Double check that pin 14 on all CD4033's is connected to ground and not floating. If displays are still lighted, pick one circuit and trouble shoot till you get it working. A couple of easy things to try that might give us a hint: 1. turn off...
  18. E

    LTspice, Warning node is floating

    Like I said in my previous post, you don't need to change the prefix attribute if you've used "model" statements to define the device. Model statements are contained in the standard.dio file, so you should be able to just select a diode from the component menu,place it on the schematic, change...
  19. E

    LTspice, Warning node is floating

    Hi Vinasse The Viper needs feedback from the output to provide regulation so the 12v voltage source doesn't really belong there. There is something not right with the Viper spice model. Also, If you want the AC supply voltage to output 230v AC (RMS) set the value to 325v. To verify setting...
  20. E

    LTspice, Warning node is floating

    The VIPER16 model is encrypted. You will have to talk to the model supplier to work out why its not working, unless they will provide you an unencrypted model file. Then we might be able to help. eT
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