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  1. K

    Float switch circuit for fish tank

    per your description of the switches and shrtrnd's description of a circuit Ken
  2. K

    Float switch circuit for fish tank

    I think it can be done, but what do you mean by "float=on" and "float=off"? Ken
  3. K

    Transformer

    Remember that the 50V is the peak voltage with no load across your capacitor. This will drop toward 35V with a heavy (20A?) load. But, will be somewhere between 35V and 50V, depending on the load at any given moment. If you need a constant 30-35V with that current level, you will need a...
  4. K

    I am sick of lasers.

    And you think the Borgs didn't complain about all the hassle of setting that up. ;) What you need to do is to purchase a pre-aligned "laser curtain"...but then you have to pay for the hassle of the manufacture aligning them. :eek: Ken
  5. K

    Generally bad ideas.

    Why do you want to destroy it at all? :confused: With higher than rated voltages motor draws more current than the internal wiring rated for. This produces a lot of heat that the motor is not designed to dissipate. Heat degrades insulation and dries out bearing lubricants. Higher voltage...
  6. K

    picaxe sprinkler

    Off the shelf: http://www.mpja.com/prodinfo.asp?number=18194+RL Or is that too pricey for your project? Ken
  7. K

    versitile microwave sensors/detectors

    I agree with Ian. I think you are at this stage with your "black box" :http://socsci2.ucsd.edu/~aronatas/project/cartoon.math.gif ;) Ken
  8. K

    Polarised C8 Inlet Power Connector

    Soldering to them should not be a problem...they're meant to be soldered anyway. Ken
  9. K

    Polarised C8 Inlet Power Connector

    If you could use a snap-in: http://www.alliedelec.com/search/productdetail.aspx?SKU=6893638 Schurter lists yours as a 2577, but can't find a source. Maybe email Schurter? Ken
  10. K

    thermostat to run light bulb or small heater to prevent freezing

    Also, there are temperature gradients in a space with calm air...colder at the floor. Ken
  11. K

    thermostat to run light bulb or small heater to prevent freezing

    Cool! Another one...cheaper...but, may not be with shipping. Ken
  12. K

    thermostat to run light bulb or small heater to prevent freezing

    I finally found the current consumption for the circuit...50mA. So any 12VDC "wall plug transformer" rated for higher current than that should work. Ken
  13. K

    thermostat to run light bulb or small heater to prevent freezing

    Just a 120VAC-12VDC wall wart to power it. If you need to control higher currents, you could add an outboard relay or SSR. Ken
  14. K

    thermostat to run light bulb or small heater to prevent freezing

    If you want to do a kit: http://store.qkits.com/moreinfo.cfm/FK934 Looks like the relay is rated for 7A@250VAC. Ken
  15. K

    Cross Zoning, not just two sensors...

    This is an analog comparator level detector. It has 6 inputs, but you can have more or less. The sensors are set for 12V-output on detect. RA thru RX, and R1 form a voltage divider. The detection level is set by R2. R2 is set for 7.0V on U1's pin 3. The voltage on pin 2 depends on the number of...
  16. K

    Cross Zoning, not just two sensors...

    Lots of possibilities, but I'm not familiar with the ProSYS keypad system. Does it need to identify which two of the ten sensors were tripped, or just that two have been tripped? Ken
  17. K

    Help a beginner with a relay problem

    I tried it with a 27Ω series resistor, a 50Ω resistor (to simulate the relay), and a 3300UF capacitor. It took ~ 0.15 seconds to reach 8V across the "relay". Don't know if that would be long enough. Ken
  18. K

    Help a beginner with a relay problem

    I don't have an automotive relay, or a circuit simulator to try this. Place a 33Ω resistor in series with the wire from the reverse switch to the relay. Place a 2200uF/25VDC capacitor across the relay coil. (+) on the capacitor goes to the resistor side. This will allow a maximum of only 2/3's...
  19. K

    Cross Zoning, not just two sensors...

    What are the sensors? How are they powered? What are their outputs? What is the circuit that they are feeding? Maybe, more details and a schematic of what you currently have? Ken
  20. K

    relay control circuit

    Another option. For a 24-28V supply use a 12v relay. R1 and R2 are selected to have the the same resistance as the relay coil. C1 should have at least a 16VDC rating. The down side is that the circuit is always powered, whether the relay is open or closed. Ken
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