Does anyone see anything wrong with this circuit?

[Toreywood]

Also how can I stop the current at point A when the capacitor near point B is charged? The load is 1 second bursts at random intervals about 1 min apart.
Thoughts are appreciated.
Torey

 

[banjo]

What are you trying to make? The transformer, as drawn, appears to be reversed. I base this on the fact that you want a higher voltage, but the transformer is configured as step down.
Please add more details about the purpose of this circuit. What is the oscillation frequency? What is the turns ratio? What transistor are you using?

 

[FvM]

I understand, that it's a self oscillating inverter (a kind relaxation oscillator), operated in step up mode to generate a DC voltage. Although the circuit is very simple, it's supposed to work. The problem is to add an output voltage regulation.

If you can tolerate an idle current through 4K7 resistor, you can use a NPN transistor to short B-E of the switch transistor to shut down the inverter. A Z-diode with a series resistor can be used as voltage sense, if the isolation can be canceled. Otherwise you need an optocoupler.

 

[Toreywood]

Yes I see I switched the primary and secondary.
The transitor I beleive is a 2n3055 I don't have the original drawing with me right now.
This is going to be a starling control device. Where the bird lands on the points and it will be dispatched.
I have figured out that I need a around 220VDC. I beleive that I can adjust the output voltage by adjusting the input voltage. Right.
As for the tranformer this is it
https://www.alliedelec.com/Search/P...70017&SEARCH=2270017&DESC=6K10HF#tab=Overview

 

[banjo]

Are you trying to scare the birds with the electrical zap or kill them? Either way, 220VDC may not be sufficient. The foot of birds have dry tough scales and little blood flow. Also, you have to be concerned with what happens when a bird, dead or alive is stuck across the plates.

Do you want to turn the transistor on and off to limit the output voltage or to extend battery life?

Do you need the secondary to be isolated from the primary? If they can share a common ground connection then feeding back a control voltage to turn off the transistor is lots easier.

If you must remain isolated, then probably and opto-isolator is the best bet. Use a resistor voltage divider across the high voltage output. The divide tap then is connected to a zener in series with the LED portion of the opto. When the voltage divider reaches the zener turn-on value, the LED turns on in the optocoupler and the output section of the opto then shorts out the BE junction of the transistor. The circuit will stay off until the voltage divider bleeds down the capacitors, then it would automatically refresh itself.

What happens at night? Do you turn it off? While many people are resisting the trend, this sort of control project is really best done in a microcontroller. They are cheap, take few external parts, and can be tailored for many different scenarios. Sure, you have to write the code, but that too is not the task it was several years ago.