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  1. AnalogKid

    Some Help With Volt Scale Reversal Needed For An Idiot.

    Yes, you can connect resistors instead of LEDs. My mistake - the 3914 outputs are programmable up to 30 mA per pin. These are constant-current outputs, so if your external voltage and resistance cause a current less than the programmed value, the output saturates like an NPN transistor. ak
  2. AnalogKid

    Segment counter with IC 555 & IC 4026

    While I'm certainly not defending the 555, two comments. First, I've never seen the noise filter capacitor on pin 5 do anything useful, and I've been looking since the 70's. Second, the cross conduction current spike is large, but very brief. Normal power supply decoupling at the device pin...
  3. AnalogKid

    Some Help With Volt Scale Reversal Needed For An Idiot.

    Note that 450 is not half way between 132 and 1954 on a linear scale. The sensor is non-linear, and the gauge has a complimentary non-linearity to produce a linear display. While it is possible to turn your pressure sensor into the correctly non-linear analog voltage to exactly match the gauge...
  4. AnalogKid

    Segment counter with IC 555 & IC 4026

    Found it. There are errors on the schematic. C2 should be connected across the switch to debounce it, not the output of the 555. Also, there are two problems with the 4026 driving a display directly. First, the schematic does not show any current limiting resistors between the 4026 and the...
  5. AnalogKid

    Segment counter with IC 555 & IC 4026

    Page not found error. Don't trust a link. Please clip and post the schematic. Why do you say "But, of course, it won't work." What are the typical segment currents of the old and new displays? ak
  6. AnalogKid

    Pulse frequency reduction circuit

    The 4017 is a decade counter, so if you need a divid-by-10 output, you do not need to connect any of the outputs to the reset input. Each output individually is the input frequency divided by 10 with a 10% mark/space ratio. The only difference among the outputs is that each one is shifted 36...
  7. AnalogKid

    Pulse frequency reduction circuit

    Depends on what you mean by "form". If the signal is a 12 V peak-to-peak square or rectangular wave, it can easily be divided by 10 with common ICs. The output waveform might be a symmetrical square wave (50% duty cycle, high 50% of the time and low 50% of the time), or a rectangular waveform...
  8. AnalogKid

    Diode Bridge

    Note that the output will not be clean DC. It will be full-wave rectified AC, so your meter reading might be off. ak
  9. AnalogKid

    Power circuit question

    AC or DC
  10. AnalogKid

    I have created a circuit could anyone plz tell me if this circuit is right!!?

    Why not. Power connections notwithstanding, the input and feedback look like an inverting amplifier with a gain of -13. -0.35 in, +4.66 V out. ak
  11. AnalogKid

    I have created a circuit could anyone plz tell me if this circuit is right!!?

    http://www.ti.com/lit/ds/symlink/lm741.pdf ak
  12. AnalogKid

    Hall effect with 5 amp draw

    The requirement in post #1 is for a low side switch. Did that change? ak
  13. AnalogKid

    Low Cost MRI Machine

    Magnets up to 4 T are approved for patient scanning, with research machines up to 20 T. ak
  14. AnalogKid

    74HC oscillator, how fast?

    Is 812 mV the dimension of the vertical measurement bars? ak
  15. AnalogKid

    How to distribute audio signal from DAC

    What are the "receivers"? Do then have input coupling (DC-blocking) capacitors? Are they located on the same board as the DAC? If not, then shielded cable should be use for the interconnect. Check the uC datasheet. You might be citing the pin's output current capability when acting as a...
  16. AnalogKid

    Load testing

    The battery datasheet should have a number for the peak current allowed. Due to different internal constructions and materials, some batteries are specifically designed for very high discharge currents, and some are not. Ohm's Law gives you 6 ohms. Watt's or Joule's Law gives you 24 W...
  17. AnalogKid

    LM358 to make FM Audio Receiver

    Yes: You can add external components to an LM358 stage to boost the output current enough to drive a small speaker, but it is a lot of effort compared to using an LM386 and the result will not be as loud. ak
  18. AnalogKid

    cheat sheets

    What is the decades-old schematic? Can you post a scan or photo? ak
  19. AnalogKid

    Help with solar switch

    You can. That will work as an alternative to a true tracking circuit with hysteresis to prevent hunting. But something will have to reset the system to the morning position, a task that is a natural consequence of a differential tracker. ak
  20. AnalogKid

    Help with solar switch

    Or something like that, depending on the load your control system is driving. That board reduces the number of things to be soldered, but some soldering is in your future. ak
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