Search results

Search Forums New Posts
  1. BobK

    What is the best Program to Design PCB

    Do you want this to make your our PCBs or to have them manufactured? This matters. The easiest software I have seen and I use for my own PCBs is the free proprietory program from ExpressPCB. You can learn to use this in an hour or so and print your PCB patterns on a laser printer for toner...
  2. BobK

    Really Need Advice Making Micro Wind Farm

    The reason Steve is complaining is the you use Wh and W interchangeably, and using W/h, which is nonsense. He explained it, and you continue to do the same. Learn what the units of power and energy are, and what those two things mean, then you will be able to communictate correctly. Bob
  3. BobK

    DC motor Speed Control with high current and potentiometer

    An H-bridge is not the same thing as a PWM controller. A PWM controller merely turns the motor on and off at some frequency and duty cycle. It can be combined with and H bridge which allows you to reverse directions, but if you want to run in only one direction an H bridge is not necessary. Bob
  4. BobK

    Hiding a momentary push button.

    Another possibility is a photo detector behind a small hole. Block the hole to trigger the button. This, of course, works only if it would normally see some light when in operation. Bob
  5. BobK

    does someone know the function of R6,R8 and R9?Is it just current limiting

    I agree. The R8 and C6 are to isolate the amplifier from the output stage. That only works if the battery is placed as Chemelec has done. Bob
  6. BobK

    Diode for thermostat circuit

    I think what you need is an extra relay each for zones 2 and 3. The inputs of these relays would be the connected to their thermostats. And the outputs would be placed in parallel with the outputs of the zone 2 and 3 relays in the original controller. Then you link the inputs of the original...
  7. BobK

    Diode for thermostat circuit

    OK, I misread your original post. So it looks like you want this: When zone 1 thermostat is on, zoner 1,2,3,4 all run. When zone 1 is off and zone 2 is on, zone 2 runs but not the others When zone 1 is off and zone 3 is on, zone 3 runs but not the others. Is that correct? Bob
  8. BobK

    Capacitor getting hot

    You could get one dimmer with more current capability. Bob
  9. BobK

    2 audio signals to a single fm transmitter

    Just put them each through a 1K resistor connected together to the XMTR input. Bob
  10. BobK

    Capacitor getting hot

    What are the specs of the dimmer and of the LEDs you are driving with it. It sounds to me like you are over stressing it. Bob
  11. BobK

    Floating Dc Current Source

    Niether DACs nor voltage regulators are sources of power. A power source might be a battery (probably best for your project) or a linear or switching supply powered by mains. What you want is probably neither of those. If you want a constant current, you use a constant current source. Google...
  12. BobK

    Boost converter + PWM +capacitor + many LEDs

    Run half the LEDs for 25% of the time, then the other half for 25% of the time then all off for 50% of the time. Edited to add: Or, if the boost converter has a current limit, set the current out of the boost converter to be 25% of the current the LEDs full requirement and run them without...
  13. BobK

    Diode for thermostat circuit

    It appears that you have two conflicting requirements: 1. All zones should operate whenever one is calling for heat. 2. Sometimes, I don't want the basement or second floor thermostat to turn on the other zones. You cannot have both of these things without having an extra state, like a...
  14. BobK

    How To Make A Up And Down Mechanism Like A Grabbing Machine By A Single Push Button

    Why don't you tell us what actually happens when the button is pressed? Bob
  15. BobK

    How to talk to a usb device

    Simplest way to find out if the device actually communicates over the USB charging port is to plug it into a PC. If it is communicating via USB protocol the PC will indicate that a new device was attached. If it is just there for power, which I think is the most likely case, the PC will not...
  16. BobK

    Transistor chains

    That circuit turns the LED out when it senses light. If you simply removed the second transistor and put the LED in the collector path of the first transistor it would turn the light led on when it sensed light. But that could be changed by exchanging the photoresistor and the resistor. I...
  17. BobK

    2N3055's and heat

    A center tapped transformer cannot be wired for double the current at half the voltage. A transformer with 2 windings (4 wires) can. If your transformer is like that, you could have a switch to have 2 ranges of voltage and you would save power on any voltage < 18V when using the lower range...
  18. BobK

    xmas present: blinking ring

    There are small tact switches (pushbuttons) that should be suitable. Bob
  19. BobK

    Wind Energy Production

    And, since it is not 100% efficient, it will require more extra energy to power the train than you will get out of it. Bob
  20. BobK

    xmas present: blinking ring

    That size is definitely doable. You would probably want to use 2 or 3 button batteries. LR44 is a popular size that is 1.1 cm in diameter and used in many small LED devices from China. I am sure you could find another one that is a little less than 1cm if necessary. Bob
Top