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  1. colum

    12v power for dashboard camera

    I need to get a camera to record in the rear window of my car that is turned on and only when I'm driving Will this 12v battery need a v regulator Any advice on type of camera or general advice would be appreciated This setup is for security reasons and all manually operated Thanks, colum
  2. colum

    Maximum circuit size posting

    I want to send circuit images what is the best size ? Thanks, Jeff
  3. colum

    AC generation

    I want to use 555 as pulser to a 4000 series IC that will split into 2 alternating pulses I want to use 4000 ser IC but I lost my diagram and I believe it was a 4011 or 4017. and then another 4000 ser to boost the output to Transistors Thanks, Jeff
  4. colum

    Antique meter

    Sorry I cannot supply photos at this time I have an old Meter from the beginning of transatlantic phone service. It consisted of a bulb as a light source and a tiny mirror suspended on a very thin wire and that wire was connected to the magnets center and rotated in a magnetic field so at rest...
  5. colum

    DC ground

    I have 1 DC circuit at 9v and another at `12 to 24v DC that are powering different sections Question Can I use a common ground for these circuits or do I need to isolate each Many thanks...Jeff
  6. colum

    PWM drive

    I have a PWM drive powerful enough to drive 12v DC motors. I want to split this pulse into 2 pulses I know it can be done with ICs but then I would have to increase the power all over again Perhaps Transistors ?? Thanks colum
  7. 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
  8. 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...
  9. 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...
  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

    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
  12. colum

    Solar cell power

    I have 2 x 7v Solar cells in driving a small 6v DC motor at 7v it will not start until I push the shaft and then it runs with good speed and powers a music box easily Without using a relay capacitor booster is there anyway a capacitor would work on a 2 wire DC motor or is there another...
  13. colum

    Wanted: 350-450 Hertz at 120 V

    I need a 350 to 450 Hz variable at 120 v to drive small motors and Hz meters probably about 15 watts. this is to test old military meters only to see if they are working....Thanks...Jeff±±
  14. colum

    Replace IC 4049

    The 4049 in this circuit overheats and quits working. This IC is supposed to increase the power to drive the transistors and has alot of wires and seems like a big complication. Could it be replaced by 2 transistors with enough power to drive the IRF510
  15. colum

    ic 4027 wave form

    The circuit is a divide by 2. With the current wiring the output pulse is all over the place fast slow large small The input signal is from a 555 and is stable . could someone suggest a repair or different wiring Thanks...colum
  16. colum

    Solar cell soldering

    I've been soldering for many years but my first attempt at connecting wired to a solar cell has been pretty bad. I used 60-40 fluxed thin my best connection was by fluxing the silver line first and then heating a drop of solder on it and then applying the heated silvered wire to the drop. I...
  17. colum

    Analog frequency meter

    I want to hook up an old analog needle type Hz meter but the needle swings wildly even with a stable Hz source...any ideas why and how to fix..Thanks....colum
  18. colum

    400 Hertz at 120 V

    I want to drive a Vibration meter at 400 Hertz and 120V and about 5 t0 10 Watts (a guess) I wonder if someone would suggest a circuit and if a 60 cy transformer can handle high Hertz This is going to be a onetime testing for several instruments and I would like to do it without spending too...
  19. colum

    Timer 555 voltage

    I want to apply two 9 volt batteries to a 555 timer supply to make 18 volts but according to instructions a 555 timer calls for 15 volts max..Other than using one battery for the timer..What is the best way to reduce the voltage to less than 15...Thanks....colum
  20. colum

    Laser

    I want to activate a sensor with a Laser but the Laser must stay on in order to activate a sequence The ones I see are pointers and are only on when the button is pressed. I would appreciate any advice....Thanks...colum
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