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  1. dorke

    Temperature Control SSR Help

    I know, You should take into account the fact that the controller's relay contacts will switch a very low current(mAs).Thus it will have a very long life. If you like to use the "pulse" output ,you should get the complete info about it's operation. Try contacting the controllers manufacturer...
  2. dorke

    Hot-swap dual battery setup.

    I think you can use the LTC4417 for this job ,
  3. dorke

    D Flip Flop Question

    Let me add, "7474" is a generic name. Please provide the full part name including all the letters in it-they are very important .
  4. dorke

    Repairing my old Wega V-3840-2 amplifier

    1.The diode D201 is SV04F. 2.The Trs you are talking about are probably not the originals. 3.If what you say is correct and the noise is only related to the R-ch , than I would check C314,C270,C272 for the possible cause. 4.What test equipment if any do you have?
  5. dorke

    Teardown: Car Insurance - Telematics Black Box

    1.The Telit GE856-quad is the processor. 2.Since they can GPS track your location and your advances , they can time tag it and from that info get your speed info and acceleration etc. 3.It doesn't have to use a sim-card,all your "user id" can be downloaded remotely to it before/after you get...
  6. dorke

    Temperature Control SSR Help

    There is not enough info on the temp. controller "logic pulse". To turn it to a constant "1" logic signal you can use the out2 of the controller like so.
  7. dorke

    I have an old Bose wave radio model AWR1-1W

    It looks like an F-type female connector,does it have an outer thread ? It can be connected to the wall FM antenna if there is one in the home, or use a 75 ohm unbalanced F-type indoors antenna. Note: A short (about 30cm) "electric rigid wire " could do the job if you live in a place with good...
  8. dorke

    Input Jack - 19v. But out the connector is 0.4v?

    Yes could be any component. What is the "board ? What is the adapter or charger. can you give brand and model? please take good photos and post them.
  9. dorke

    LDO gets hot when using a relay module?

    So,How "hot" does the LDO get? to answer this we need to know which part is it. Pd(LDO)=4*85mA=0.34W Thermal resistance of a TO-220 packages case-to-ambient is about 50°C/W to 60°C/W. Tcase over ambient temp. =0.34*60=20°C so for a 25°C room we get 25+20= 45°C case temp. this can't be related...
  10. dorke

    LDO gets hot when using a relay module?

    Dave you are correct. I did write in post # 21: "Switch" S as before The op did that already in post #1 (that isn't the problem he faced): "When the signal (S) pin is low, the module and LED are off. When S is high, the module and LED are both on."
  11. dorke

    Input Jack - 19v. But out the connector is 0.4v?

    It could be a short. It could also be too much current drown by the board ,is the charger the "original" one?
  12. dorke

    LDO gets hot when using a relay module?

    I would suggest you use a power source of 4.5-4.8V and not the 9v battery with the LDO. You can do that with AAA batterys 4*1.2v or 3*1.5V . "Switch" S as before. you may need to recalculate the series resistor to the LED.
  13. dorke

    LDO gets hot when using a relay module?

    From the #1 post: "When the signal (S) pin is low, the module and LED are off. When S is high, the module and LED are both on."
  14. dorke

    LDO gets hot when using a relay module?

    Recalculating the LDO power disipation The max module current is about 85mA(from the data steve posted) it agrees with the following: 71.4*1.1 (nominal coil current +10%) +3.5/1k(on borad red led)=82mA Pd(LDO)=4*82mA=0.33W. The funny thing is the board already has the LED to turn on...:rolleyes:
  15. dorke

    LDO gets hot when using a relay module?

    Here is the schematics of the Module. The relay is not driven directly,Tr Q1 drives it.
  16. dorke

    LDO gets hot when using a relay module?

    The relay is srd-05vdc-sl-c from songle As can be seen it's coil resistance(nominal) is 70 ohm and the coil current is71.4mA Nominal voltage is 5V but it can be operated down to 75% pull-in that is 3.75V The relay as 5 "legs", not 6 as your original drawing shows ! 2 for the coil 3 for the...
  17. dorke

    LDO gets hot when using a relay module?

    BucketOfFish, Could you please take a good photo of the relay both from the writing and the "legs" and post it here? it may clarify things.
  18. dorke

    Open / Short circuit time constants for pole approximation

    The Electrician, You are correct my result in this form is an approximation: Lets divide the last eq. by re*rpi we get: [R'L+R'sig]/ [1+R'sig/rpi +R'L(1/re+1/rpi)] equation - ***- Note that rpi=re(beta+1) thus 1/re>>1/rpi so the 1/rpi term can be omitted and we get the book's result...
  19. dorke

    Cannot find datasheet or replacement part - flyback transformer

    Try searching by the monitor brand and model. If you can find it's service manual,it may lead you to the part you need.
  20. dorke

    Where did this go?

    Where did it go? NO where commercial yet(cost?),still in research mostly. It also took a tour to flexiable-plastic. And an interesting tour to the security-side of life
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