Search results

  1. T

    Automatic ranging current sensing

    I think we might as well proceed with the hijack! We should first thank the OP for his clear schematic. The schematic makes some sort of answers possible even if we have lost the OP for the moment. Of course, he might have given us a link to a data sheet for the LTC61102. Here's one to look...
  2. T

    Cfl lamp from 3.7volts project.

    Steve, I kinda fast-forwarded through the video. After a few shots of the hardware, there's a pretty clear view of a schematic. I didn't listen to the audio, perhaps that sheds some "light". I still hope the thread's owner will put his schematic up where we can easily see it. A screen...
  3. T

    Cfl lamp from 3.7volts project.

    You should post a clear ( still!) copy of that schematic. Someone will explain why it doesn't work, and perhaps suggest measures you might take. It might help if we knew how much current can your intended battery provide, as well as how much power the lamp requires to start. Ted
  4. T

    Amplifying current in a sine wave

    Thanks for posting the link to a data sheet for your valve. That helps us understand much better what you need. I hope you have already solved your problem, but here are some thoughts that might still be of use. As the original post suggested, there is no need for a complex drive circuit...
  5. T

    16 Volt DC conversion to 12 Volt AC

    You could use a power oscillator driving a 50Hz step-up transformer. The oscillator might use an automotive audio power amplifier IC, or else a few discrete parts. The classic Bill and Dave in the garage oscillator topology is not hard to get working. You may have to wind your own...
  6. T

    Driving a 12 pins LED display

    It is indeed bad form to run multiple threads for the same topic. Perhaps a moderator will do some amalgamation. What we need to start: Two threads, same topic: Driving a 12 pins LED display https://www.electronicspoint.com/threads/driving-a-12-pins-led-display.275486/#post-1668994...
  7. T

    Daewoo DMC80C39 CMOS Single Component 8-bit Microcomputer

    I believe the 80C39 has no program memory on-chip. It was intended to work with an EPROM. This microcontroller family from Intel originally had only mask-ROM for on-chip program memory. I'm sure you can find a free assembler somewhere online. You may have to run it under DOS. Or, a UNIX...
  8. T

    555 PWM 0%?

    Navivanuva, A practical solution might be to add a resistor from the timing circuit to the positive supply. The resistor might connect to the "dim" end of the 50k control, or to the arm of the control. The value for this resistor should be a bit over 100k. You might try 100k for a start...
  9. T

    Bidirectional Current Source

    Shehroz, I'm with Harald, I'm sure we are missing a few things here. Any chance you could explain a bit more about how this circuit is supposed to work, and what it will be used for? For instance, do you need an output current that changes amplitude with input voltage changes? Some sort...
  10. T

    Clean square waves using a 555 timer?

    Xeno, I have attempted to read the whole thread from the beginning, then address the more interesting issues outstanding. Please forgive me if I failed to take note of something I missed along the way. Not all "555" timers are the same. Even bipolar parts vary among manufacturers and dates...
  11. T

    Mosfet / Gate drive problems

    The early schematic that included the load inductor showed one end of the inductor tied to the negative power supply. The FETs can only drive the other end of the inductor positive. This will result in a really big DC component that will just make things get hot. I don't have the time to...
  12. T

    How to measure DMM's current circuit resistance?

    Do you have a second meter with a resistance range? Just measure it! The meter under test need not be turned on, but the current range of interest must be selected. The most common voltage burden for DMM current ranges is 200mV full scale, for all current ranges. So higher current ranges...
  13. T

    Driving a 12 pins LED display

    I believe you are correct. Pin 13 cannot be left adrift. There are other problems with this design, starting with the choice of a 74HC595 to drive the display. If that's your application, you might want to use another part. It seemed that the original poster lost interest, or perhaps he...
  14. T

    D-Sub crimps

    Sarunas, For real production, a harness or cable house ( job shop ) is the answer. Depending on where you are, a connector manufacturer's sales office should be able to refer you to some suitable sources. Local industrial directories, or electronics distributors might also help you find a...
  15. T

    Driving a 12 pins LED display

    I think it's a bit harsh to say that the linked pictorial diagram provides no information. In conjunction with the LED display datasheet, also linked, one might figure out what's going on. One would also have to look up the 74HC595, as well as the controller board. The real point is that...
  16. T

    Db25 Panel Mount

    You can mount the connector shell on a subplate, then mount the subplate to your main panel. The opening in the panel must be large enough to clear the mating connector's backshell, or hood. A single subplate might carry several connectors. It helps if you have some means of making odd...
  17. T

    SCR and Zener regulator question

    If this works at all, it is as a shunt regulator. It is possibly that the three phase AC source has a high enough impedance that a shunt regulator is satisfactory. When the zener diode conducts enough, all three AC phases are shorted to the + bus. Each AC phase is released when that phase's...
  18. T

    Astable 555 Circuit Problem

    Matt, A few questions for you. You said " I am using a TI 555cn IC ". TI use the suffix "CN" to define the grade and package. Just 555CN means a bipolar part, such as the LM555CN. You might want to use a CMOS version, such as the TI LMC555CN, or TLC555CP. The CMOS versions draw much...
  19. T

    74HC logic output signal

    John, How was your scope probe grounded? For sure, you can't omit the ground wire from the probe to your circuit, and the short ones work better than longer ones. If you can, clip it right onto the Vss lead of the bypass cap on the CMOS part you are observing. Sometimes it's instructive...
  20. T

    Help Me Understand This Inverter Circuit

    PS: I just realized that my zener network notion is rubbish. You need a network that responds to current, or to voltage times time, to simulate the transformer core saturation. A current limiter in the +24 line might work well enough, also.
Top