Does anyone see anything wrong with this circuit?

[toreywood]

I am new to electronics but have a basic understanding of the science.
Does anyone see anthing wrong with this circuit?
Maybe I should have said what is wrong with this circuit.
And What can I do to shut off the flow of the battery when the capacitor near point B is charged.
My goal is to get anywhere from 120VDC to 450VDC from a battery 6V to 12V. I only need a .5mA current occuring at 1sec bursts at random intervals anywhere from 2 sec. apart to 2hr. apart delivered to the load. These bursts are going to be triggered by an input from a outside sorce. (i.e. a starling landing on positive and negative points)
Thoughts are apprecitated.
Torey

 

[blueroomelectronics]

Plenty wrong with the circuit, where did you get it?

 

[toreywood]

I found the inverter part on the net and added a rectifier to make it DC. And a capacitor to create a burst when the points are closed.
How can I fix it?
I did say basic knowledge of electronics right.

 

[blueroomelectronics]

What are you trying to build exactly? What is it for?

 

[toreywood]

sent you a PM

 

[Andy1845c]

(starling landing on positive and negative points)

Are you trying to electrocute birds? Not a real practical idea in my opinion. Is your intent to kill them or just scare them away?

 

[toreywood]

Yes my intent is to kill these birds. I live on a dairy farm and currently I estimate the starling population to be 500. These birds carry diseases such as Johne's. I am looking to start a starling control business. The only way to control these birds right now is to have the US department of fisheries and wildlife to come out and poison the birds the problem with this is the birds are laying all over the farm when they are done. If they are shocked they will fall in one spot. And the USFW charge $500 each time they come out. A $100 device would go a long way.
Torey

 

[Andy1845c]

The first problem I see is getting them to land where you want them to.
If you string up a wire do you think they will land on it and do you think any protected birds would land on it?

Also, if you make something powerful enough to kill a bird, it has a pretty good chance of killing a human that touches it by accident.

You might need more then 450v. An electric fence is normally 50K+ volts, but the current is very small. The huge voltage helps ensure it will shock through thick fur and such. I am no expert on this, but the worst way for a human to recieve a electric shock is from one hand to the other. The heart is in the path of the current and has a good chance of being stopped or otherwise harmed. I don't know where the heart in a Starling is, but I can't see how you could get the current to flow from leg to leg, let alone through the heart. If you had a wire with 2 conductors, insulated from eachother, but where the bird would grab both with its feet, I think you'ed get a current path across the toes and I am not sure that would be a clean, humane way to kill it.

Just a few thoughts. Have you seen any devices like this that work?

 

[toreywood]

My plan is to use a small bird feeder like they use for posioning and where they perch to eat will be a rail. This rail will be composed of positive and negative sections about a half inch long each and about a half inch between them. The actual dimensions will be adjusted with experiment and observation. Yes human shock is a possiblity. I don't think protected birds will be in danger I intend to use it in the rafters of the barns. And I have yet to see protected birds in the barn. I understand this could all be a flop in the end but the only way to find out is to try it. It could end up being a stunner more that a dispacth but if it is I will just put a funnel under the feeder and a one way valve at the bottom of the funnel leading to a cage.
I have thought this out in depth and all I need now is the circuit and my plan will be on to the work bench.

 

[toreywood]

No I havent seen any devices like this. Did Alexander Bell see a telephone before he invented it?

If it proves to be a effiecent way to solve this problem I am thinking about patenting it.

A safty note: After I get the circuit in order and if it works I plan on modify it with more saftey features like a switch to drain the capacitor.

 

[Andy1845c]

Does it need to be battery powered? Can you power it from a wall outlet?

 

[Andy1845c]

You may have a rough time selling this commercially, even if it works. Its just far too dangerous. You could easily have a lawsuit on your hands.

There have been several topics here about killing mice with high voltage. I have yet to see a working high voltage electric mouse trap sold. I think its hard to get a clean kill, and very dangerous to humans and pets.

I have seen mouse trap setups that use an electric fencer to stun the mousre, causing it to fall into a bucket of water and drown. This is safer, but still not real practical.

You may have better luck seeing if you can stun the birds with a fencer and make them fall into a trap like you are thinking. The only thing I don't know is if a shocked bird tends to drop or fly off.

You can add a bleeder resistor to ensure your high voltage capacitor drains when the power is removed. Not many switches will handle high voltage.

 

[toreywood]

I don't really want to do that because of stray currents. The farm has alot of precautions they take to eliminate it. I want to have the unit suspended by an insulator to take this chance for stray current as near zero as I can. Running a extention cord to the unit will just provide a path for electrons. It would make it a whole lot easier though.

 

[toreywood]

I have pondered the sell and liablity thing also. I will have to think more about that when I get this working.
Is the bleeder resistor just a high ohm resistor?

 

[Andy1845c]

Is the bleeder resistor just a high ohm resistor?

Pretty much. Its value will depend on your voltage and capacitor size and how fast you want the capacitor discharged to a safe level when the power is off. It will waste some power though, and that will be an issue with a battery powered device. It might not be practical to have one, but would make the device vary dangerous to touch, even with the power off. You will certinly need a way to ensure the HV cap is discharged before you move or work on this.

What kind of battery were you thinking of using and how long would it need to last?

 

[crutschow]

An AC voltage is generally more lethal than DC, so I think you want to leave the output of the inverter as AC, not rectify it. AC can cause lethal heart fibrillation, whereas DC acts more like a defibrillator.

To minimize power from the battery you could pivot the perch and add a microswitch with a small spring that would apply power only when there's the weight of a bird on the perch.

 

[toreywood]

I would like to use a Sealed lead acid battery mainly because I can recharge it and I have one. 12V 5Ah. It would be handi to have the battery last more than 24 hr. That way I could have two per unit and each day swap them and charge the one not in use. But it is definitly not a problem if I could only get 6-8 hrs. out of it.

The only reason I switched it back to DC is so I could use a capacitor. Do you think it will deleiver an adequate shock without the cap?

 

[toreywood]

If I used a microswitch would that control the juice from the battery? If I did this would the amount of time that the switch closed charge the capacitor the same amount that is being discharged? I would think that it wouldn't because that is the point of having a cap there to deleiver more charge than what can normally be deleivered through the battery. I agree AC would be better.

Correct me if I am wrong you guys are the experts.

 

[toreywood]

Plenty wrong with the circuit, where did you get it?

What is wrong with it? Will it not deliever my charge?

Any help is appreciated!!

 

[crutschow]

Wikipedia states that 60mA of AC through the chest can kill a human but it takes 300-500mA of DC, so I would expect that either would kill a bird also. And a long duration shock is probably more lethal than the short shock from a capacitor, which may tend to just stun the bird.

Yes, you would use the microswitch to control the power from the battery. But, as you say, that would not work well if your charging a cap, only if you are applying an AC voltage directly from the inverter.