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  1. KrisBlueNZ

    Does this dc - dc booster have regulated Vout?

    I have to answer, read the data sheet. Look in the pin descriptions section. There's a description of the PFO pin there, and there's probably a more detailed description later in the applications section. Can you point us to the buck-boost converter? I would be interested to see it :-)
  2. KrisBlueNZ

    Does this dc - dc booster have regulated Vout?

    No, the PFO pin is just an output. The chip doesn't care what you connect to it.
  3. KrisBlueNZ

    Does this dc - dc booster have regulated Vout?

    I wouldn't power any device that expects a particular supply voltage (e.g. 6V, 3V etc) from the solar panels directly. According to the description of the PFO pin in the datasheet, it's an output that signals when certain bad operating conditions are present. So you don't need to connect it to...
  4. KrisBlueNZ

    LDR circuit.. no luck :(

    You're going to need a lot more than an LDR. An LDR is not a switch, and it cannot pass the high currents your lamp will be drawing. You will need some circuitry in between the LDR and the lamp circuit. Have a good look inside the lamp unit, and see how the solar input, the battery, and the...
  5. KrisBlueNZ

    Does this dc - dc booster have regulated Vout?

    So let me get this straight. You have a 5V solar panel, rated at 3A max, and you're charging a pair of series-connected supercaps from that panel using an LTC4425 supercap charger IC. Now you want to generate several output voltages from the voltage on those supercaps. Right so far? And you've...
  6. KrisBlueNZ

    Help with transistor switches please!

    So you want to wire some circuitry in to the remote control transmitter so you can make the remote controlled vehicle move and turn, by simulating presses on two centre-OFF rocker switches on the RC transmitter, is that right? The simplest answer is relays. Reed relays are ideal but any kind...
  7. KrisBlueNZ

    Does this dc - dc booster have regulated Vout?

    I'm sure everyone here would be able to help you a lot better if you gave us all the background information on your project. What is the incoming power source? What output voltages do you want, and what current rating do you want for them? Do you have specific loads that you want to be able to...
  8. KrisBlueNZ

    Help with time delay relay circuit

    Looks good to me Andy.
  9. KrisBlueNZ

    What value of resistors do I need and a sanity check

    I don't know what to do with an ms11 file. Maybe you could upload a screen shot of the simulation and results. I should be able to check that.
  10. KrisBlueNZ

    Valve (tube) amplifier schematic help

    If you would rather use valves in the output stage of your headphone amplifier, Google "class A" "headphone amplifier" valve tube "output transformer" The first five hits are all interesting.
  11. KrisBlueNZ

    water level motor operator

    The sensors are lengths of non-corrosive metal which hang down into the tank. When the water level reaches the bottom of the metal, a small current flows through the water, and this current is detected by the circuitry connected to the metal. This is a very poor way to detect water level, for...
  12. KrisBlueNZ

    Multi Resonant Circuit

    You should be able to use two L-C circuits together. If you're using parallel tuned circuits, connect the two of them in series, and vice versa.
  13. KrisBlueNZ

    Clamp a floating input

    So you're using a BS170 to drive the relay, are you? It has a gate threshold voltage of a few volts, and no hysteresis. That's fine. As long as your DRL/LOW signal doesn't do anything different from what you described, you shouldn't have to worry. Good luck :-)
  14. KrisBlueNZ

    What value of resistors do I need and a sanity check

    I've been asked to write up a parts list. This list matches schematic revision 002 (apart from the RV value, see below). BT1 Battery 12VDC -- whatever you want to use. A battery holder with AAA or AA cells is probably a good idea. DZ omit DR 1N4007...
  15. KrisBlueNZ

    Clamp a floating input

    The main advantage of my second design is robustness, because it doesn't use any ICs, which can be damaged fairly easily by large spikes on the positive power supply rail. As long as you have good clamping on your supply, your op-amp should be safe. I also did a simulation of it, that shows how...
  16. KrisBlueNZ

    Valve (tube) amplifier schematic help

    You got it. Actually it was +/- ~5V (volts, not mV), so the voltage has dropped by a factor of more than 1000, or 60 dB! Nice work with that simulation Chris! That shows the effect clearly. On the bottom right trace, which shows the voltage across a 36 ohm transducer, the amplitude has...
  17. KrisBlueNZ

    Valve (tube) amplifier schematic help

    Ah, if you're trying to drive headphones directly from your preamp, that will explain why there's no bass. That circuit is a preamplifier; it's not designed to drive speakers or headphones directly. Its output impedance is high, so its output signal has very little power. It has to be used with...
  18. KrisBlueNZ

    Valve (tube) amplifier schematic help

    Actually, capacitance between the signal path and ground attenuates high frequencies, and the problem is especially bad with valves because of their high operating impedances. For example, 100 pF of stray capacitance at 10 kHz has a reactance of about 160 kilohms, and would cause noticeable...
  19. KrisBlueNZ

    Valve (tube) amplifier schematic help

    A quick way to check a lot of things is to measure the DC voltage on the anode. The valve should be conducting enough to pull the anode voltage down below the supply voltage (because the anode current causes a voltage drop across the anode load resistor). Typically the anode voltage should be...
  20. KrisBlueNZ

    Clamp a floating input

    OK, here's an improved design. It adds a Schmitt trigger to ensure that the relay always turns on and off cleanly. The first part operates as described before. PNPs can cause confusion, as they are often shown upside down (i.e. with the emitter at the top). PNPs are the pin-for-pin match of...
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