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  1. colum

    Variable DC

    Thanks kellys eye They do not mail to the US. I will try for a 3055 and some variable resistors Standby for the smoke
  2. colum

    Variable DC

    I want to drive a small DC motor with a 12 volt battery I need to vary the voltage to the motor from about 6v to 9v to speed control If possible I would like a simple circuit. An ordinary wall plug in transformer works well but is not variable. Thanks for all advice Jeff
  3. colum

    Parts for projects

    I'm getting back into circuit building But the new ICs do not readily fit the ic socket they are either too loose or too tight. I will not name the supplier but I may go back to wire wrap sockets as they were always better and then again it might be a IC problem. Question What small order...
  4. colum

    Ringing Transformer

    Thanks Davenn, I just remembered I tried to use a 60 hz to a 350 hz and it did not work and now I know why you saved me from another boondoggle...Jeff
  5. colum

    Ringing Transformer

    I believe that an old system called a ringing transformer was used by the telephone company to convert 60 hz 120 v to 20hz 40 volt AC it used 2 transformers 2 transistors and 2 large capacitors and many small resistors and no ICs. I want to build one for a discrete 400 hz. I have the original...
  6. colum

    Regulated 12v supply

    Sorry not sure how that got duplicated...colum Many thanks for that information and it does surprise me the technical engineering with lo voltage DC I am more familiar with 3 and 4 phase AC Throw the switch and stand back and don't be grounded and hope the installers did a good job...colum
  7. colum

    Regulated 12v supply

  8. colum

    Regulated 12v supply

    Hi folks This power supply is meant to be a bench item to test ICs and at most recharge a small battery The capacitor requirement puzzles me The intake side is 25v so I imagine the cap needs to be 2X and the output at 12v therefore a 24v cap but the Amp rating of the caps for a general light...
  9. colum

    Regulated 12v supply

    I abandoned the 4000 ser circuit the 12v reg power supply is for the future so I just need to understand the capacitors in a regulated circuit. I'm sure they can be oversized or undersized Thanks..colum
  10. colum

    Regulated 12v supply

    I was building a circuit with 4000 ser and timer ics but I was getting curious hi frequency pulses even when the timer and capacitors was not connected..I believe it was the power supply which did die soon Could someone suggest a good capacitor combination for a 12+ ic well regulated power...
  11. colum

    555 astable

    Thanks much for the kind offer but I used all my 555s up so I will try to get a different brand and I'm determined to do all hard wirin g and fix this board.. Thanks colum
  12. colum

    555 astable

    With out any load it heats up tp the touch and with a meter it heats up so I can not get a reading because this over heating is immediate. like a dead short all of the pots are tested the capacitors were tested in another circuit It only leaves the 555 which I will get from another source...
  13. colum

    555 astable

    I know it is experimental and I have built complicated stepper motor drives by puitting in var pots and switchable caps and all hardwireing The power supply I was using overheated so it may be damaged thats why I used a battery but the 555 began to heat up Keep in mind this issue is new to this...
  14. colum

    555 astable

    I made everything variable or replaceable because I'm not very good at math or schematics so after I determine settings I redo the combinations. Thanks colum
  15. colum

    555 astable

    I'm excellent at silly stuff but in this case its my 4th try and I never give up and I triple check. Thanks colum
  16. colum

    555 astable

    I will change my supplier for sure. Thanks..colum
  17. colum

    555 astable

    GOOD point The chip has the round indentation next to the #1 - post I assumed Yes I started the pots midrange Thanks..colum
  18. colum

    555 astable

    I can not get this circuit to work I copied it from the internet and copied others from old magazines and they all overheated 555 and the power supply too. I show the physical layout in case that is the problem. All add ons are variable or replacable..Thanks for your help
  19. colum

    Solar cell power

    The battery system will not work, the voltage applied to the motor goes to zero on startup I think it will need a timer and relay to give the rechargable battery time to powerup...colum
  20. colum

    Solar cell power

    Thanks Bluejets Thats probably my best option and one I would never have thought of...colum
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