I have a small transformer I desoldered from a disposable camera that transformed 1.5V to high voltage >90V. It has three leads on one side and two on the other. I have been testing its resistance and got the following measurementsResistance (*There is an error the resistance from connection 4 : 2 is 270 ohms not 3 ohms) The 3rd lead seems to be connected to the smaller coil but there is glue and I cannot figure out the other connections.Transformer Sorry for the really terrible solder joints (working on it).

  • \$\begingroup\$ So when you test between any two pins you never get infinite resistance?? \$\endgroup\$ – Hot Licks Jan 24 '15 at 3:37
  • \$\begingroup\$ Hello, I am glad someone revived this thread since I was never able to figure it out. There is infinite resistance between pins 3 and 4, 5 and 4. and between 1 and 3, 1 and 5, 2 and 3, 2 and 5. It seems a bit strange that the middle lead (pin 4) has a different resistance to pin 1 and pin 2 but between pin 1 and pin 2 they have the same resistance \$\endgroup\$ – AlanZ2223 Jan 25 '15 at 16:59
  • \$\begingroup\$ I don't understand why you have 4:2 twice, with two different values. \$\endgroup\$ – Hot Licks Jan 25 '15 at 19:46
  • \$\begingroup\$ 4:2 resistance is about 3 ohms \$\endgroup\$ – AlanZ2223 Jan 25 '15 at 21:05
  • \$\begingroup\$ Then what does this mean: "(*There is an error the resistance from connection 4 : 2 is 270 ohms not 3 ohms)"? \$\endgroup\$ – Hot Licks Jan 25 '15 at 21:46

You might want to look at Sam Goldwasser's FAQ on strobes and camera flashes- it's quite an extensive collection. With credit to Sam and the original author, here is a typical circuit:

enter image description here

It appears your 3:5 is the drive coil and the high voltage and feedback windings are the remaining three pins with 2 the high voltage output. Up to you to figure out the phasing, and I'm not really sure from those measurements which end of the feedback coil goes where- try to use a higher resolution meter and take the measurements all at the same time (and temperature). 3 ohms is only about 1% of the high voltage winding...


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