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I am working on a Solar Powered Wireless Power Transfer project. The simulation for the circuit I am working off of works really well.

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I have built this design and others on a breadboard but I am getting a DC output across the inductors. I am unsure as to why it isn't outputting correctly.

Any help would be appreciated.

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  • \$\begingroup\$ Assembly error in the breadboard? What about values at other points in the circuit such as the base of Q1? Do you have a scope? \$\endgroup\$ – pjc50 Apr 20 '16 at 10:37
  • \$\begingroup\$ I've used two different breadboards so I don't think it is that. The base and collector are both at 6v. The emitter is at 0v. Every other point in the circuit is at a constant 6v too. \$\endgroup\$ – B. Durrant Apr 20 '16 at 10:41
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    \$\begingroup\$ If the base is at 6v and the emitter is at 0V then either it's not an NPN transistor or it's broken. \$\endgroup\$ – pjc50 Apr 20 '16 at 10:45
  • \$\begingroup\$ @pjc50: or a simple error in the pin assignment, oh wait, the OP doesn't make errors in its breadboard assembly... \$\endgroup\$ – PlasmaHH Apr 20 '16 at 10:50
  • \$\begingroup\$ Changed out the transistor, still getting the same issues. I've checked the setup on the breadboard multiple times. Don't see any errors. \$\endgroup\$ – B. Durrant Apr 20 '16 at 10:57
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If the circuit does not start oscillation will break transistors because the base is polarized and the collector is shorted to + . You should place a current limit resistor in series to positive of about 50 ohms and verify if oscillator starts. Assuming hfe about 300 with a base 47 k resistor the collector current could be about 50 mA and this could destroy quickly the 2222. What shows the oscilloscope connected to BE of 2222? Eventually verify connections of your 2222 with an ohmmeter connected to test diodes and / or hfe .

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  • \$\begingroup\$ After adding a 50 ohm Resistor in series with the Collector the voltage between BE is a constant 0.6v. \$\endgroup\$ – B. Durrant Apr 21 '16 at 9:30
  • \$\begingroup\$ So probably the gain of the amplifier is too low to start the oscillation. It seems that the phase of the coils is wrong or maybe you should try with a standard Colpitts oscillator eventually with a Mosfet like IRF 520 or similar instead of the transistor. \$\endgroup\$ – krufra Apr 25 '16 at 11:45
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Maybe it's this: -

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Sometimes you get slightly different BJT variants with annoyingly different pins names/number. There's also the generic differences that exist around the world: -

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Or maybe you've just got the pin out wrong.

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