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  1. KrisBlueNZ

    simple HF Signal

    90 MHz is just an approximate frequency. You can tune your receiver to somewhere where there's nothing transmitting, then tune your transmitter to match. Is your transmitter an FM transmitter? If it's AM, an FM radio won't receive it very well.
  2. KrisBlueNZ

    Important capacitor specs ?

    Generally if nothing else is specified, you can use pretty much anything that meets the specifications that are given. For decoupling, for values of 1 µF and less, ceramic capacitors are traditionally used, because they have low ESR and are cheap and compact. But avoid Zxx dielectrics (e.g...
  3. KrisBlueNZ

    Help understanding slow start circuit and tracking circuit in simple dual rail power supply

    OK. The first thing you need to understand is that the LM317 produces an output voltage that's equal to the ADJ pin voltage plus the reference voltage (about 1.2V). So the voltage at the ADJ pin determines the output voltage, and there is a fixed offset between them. (In your schematic, the...
  4. KrisBlueNZ

    Slow down this circuit's oscillation

    Yeah, I like the clean and sparse look. I get the same thing with my old OrCAD/SDT III. And LTSpice makes pretty clean looking schematics too. Many of the modern schematic packages use lots of colours, and unnecessary clutter - they show dots where components join to lines, they show polarity...
  5. KrisBlueNZ

    Random Traffic Light

    Steve has assumed that you want the three colours to have equal probability. If you don't, then if you can allocate probabilities so the total is in the range 3~10, you can use more of the 4017 outputs and OR some together, e.g. using diodes, to combine them. For example if you want amber to be...
  6. KrisBlueNZ

    Sequential Circuit Timing

    You don't need to break it down into "basic electronics". You just need to describe it clearly and post a schematic. Even a block diagram would help. Otherwise you are wasting the time of anyone who tries to help you.
  7. KrisBlueNZ

    Sequential Circuit Timing

    Try to imagine that you had no previous knowledge of the circuit - you knew nothing about it, but you knew what each of those ICs does. Now read your description and see whether you would be able to figure out what was being described.
  8. KrisBlueNZ

    Sequential Circuit Timing

    OK, well, when you can, we may be able to help.
  9. KrisBlueNZ

    Sequential Circuit Timing

    I can't visualise the circuit from that description. You really need to post the schematic, and describe what your circuit does, rather than how it does it.
  10. KrisBlueNZ

    New member, quick general question

    Yeah, what Steve said. And to answer your question directly: No, it's not necessarily wrong for a resistor to have voltage on one end and no voltage on the other end. Actually it's quite common. It depends on how the resistor is used in the circuit; there is no simple rule.
  11. KrisBlueNZ

    Sequential Circuit Timing

    Hi Anthony and welcome to Electronics Point :-) I can't make much out of your description. You have 256 channels, and sixteen 4067 multiplexers? So you are multiplexing 256 different signals onto a single output? Or the other way round? You have a single 4-bit counter? That only gives you...
  12. KrisBlueNZ

    Earth Pole DC Motor (No Magnet Stator)

    A motor that you can use as a compass! Cute :-)
  13. KrisBlueNZ

    555 voltage controlled oscillator question

    Good. Or you could use a variable regulator such as an LM317 so you could set the output voltage to 10V for example, or a low dropout regulator that doesn't need so much voltage between its input and output. Micrel make a nice range with output currents of 1.5A, 3A, 5A and even 7.5A. See...
  14. KrisBlueNZ

    DS1307 initializing

    I don't know what the problem is. But I don't think you should be writing to the seconds register every time your code starts up. The DS1307 is supposed to be used with a backup battery and it will remember the state of the CH bit. So if the CH bit is already 0 (clock is already running)...
  15. KrisBlueNZ

    Choosing an Opto Isolator

    Yes. The SSR's input is an infra-red LED. According to the data sheet, it has a typical forward voltage of 1.2V, and it needs at least 10 mA flowing through it to activate the output. These conditions both apply to the ON state, when your control voltage is present. The driving circuit looks...
  16. KrisBlueNZ

    stepper motor is missing the steps

    Or just being accelerated or decelerated too quickly...
  17. KrisBlueNZ

    555 voltage controlled oscillator question

    Thedrive2112, you need to separate the sections that you quote from your responses. When you're replying to a post from me, your reply has to look like this in the editor: This is your response to the text that you just quoted. If you want to quote more of my post, you need to put a new...
  18. KrisBlueNZ

    USB Chargers

    Random tangential information: There's a company in Auckland (New Zealand) selling the Samsung 2A USB charger, model number ETA-U90HWE, universal input, for NZD 29 (equivalent to about USD 25). That's the one I would go for, assuming they're telling the truth when they say it's genuine Samsung...
  19. KrisBlueNZ

    Beginner pull up resistor question

    Resistors don't "eat" voltage. They can (and usually do) have voltage across them, but only if current is flowing through them, as Bob explained. If you connect one end of a resistor to +5V, and measure the other voltage with a multimeter (with its negative lead connected to 0V), you will...
  20. KrisBlueNZ

    Effect of mechanical shock on Tantalum capacitors

    It should be easy to accelerate something small at 80,000 m/s2 - just hit it with something heavy! The acceleration isn't necessarily sustained like it is with a vehicle. Or he might be talking about deceleration; AFAIK they're the same thing from the point of view of the thing being...
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