[Moved]: Need help with auto switch polarity of a circuit

Here is what I am wanting to do and cannot figure out how to accomplish it. I want to use 3 9v Batteries in Series and run +/- 27v in to a circuit and I want +/- 27 also out of the circuit. Heres where I am unsure. Although I know I could use a switch to manually change polarity. I am wanting a timed circuit to swap polarity. The timing is not too critical but needs to be between every 2-3 minutes to swap the polarity. Also would be nice to have a way to protect the out going 27v leads as they are going to be electrodes to have some sort of protection in case they were to touch and short out. Thats not absolutely critical but would be a nice feature. I have been stuck for 2 weeks trying to figure out how to get a circuit built that will allow for auto switching of polarity. Any help and assistance or ideas would be GREATLY appreciated.

A little more info I am building a Colloidal Silver Generator the Silver Electrodes go in distilled water. The reason for reversing polarity a time intervals and back and forth is to ensure one electrode is not eroded over time faster than the other. The process takes 2-3 hours so a manual switch would be a daunting task to baby sit the generator. If some one is willing to help me complete a circuit that will work, I would be very appreciative.

Thank you
Rodney W3LDR
Amateur Radio Operator

Colloidal Silver is promoted by Quacks (not real doctors) and is not considered to be safe to use by expert real doctors. It was a "medical remedy" 100 years ago when nobody knew anything about medicine. Here is the photo of a man who took some:

Yep I am building for a buddy seen that before still need to build him one anyway he has taken that stuff for w while he says this is rare anyhow

Disregarding the safety issues, what you need is a simple two-pole changeover relay and a timer circuit. A 555 timer IC would be ideal. Use the timer to energize and de-energize the relay coil at the periods you want and connect the 27V across the common relay contacts. Cross over the NC and NO sides of the two relay poles so the voltage is reversed when the relay operates. Take the output from the cross over connections.

From 9V batteries you probably don't need overcurrent protection but if you want it there is no way except a fuse that wouldn't drop the voltage a little.

Brian.

I am probably going to use a Wall Wart for him and wire the 3 9v batteries on a switch as a backup power source per his request

gunlocators said:

Here is what I am wanting to do and cannot figure out how to accomplish it. I want to use 3 9v Batteries in Series and run +/- 27v in to a circuit and I want +/- 27 also out of the circuit. Heres where I am unsure. Although I know I could use a switch to manually change polarity. I am wanting a timed circuit to swap polarity. The timing is not too critical but needs to be between every 2-3 minutes to swap the polarity. Also would be nice to have a way to protect the out going 27v leads as they are going to be electrodes to have some sort of protection in case they were to touch and short out. Thats not absolutely critical but would be a nice feature. I have been stuck for 2 weeks trying to figure out how to get a circuit built that will allow for auto switching of polarity. Any help and assistance or ideas would be GREATLY appreciated.

A little more info I am building a Colloidal Silver Generator the Silver Electrodes go in distilled water. The reason for reversing polarity a time intervals and back and forth is to ensure one electrode is not eroded over time faster than the other. The process takes 2-3 hours so a manual switch would be a daunting task to baby sit the generator. If some one is willing to help me complete a circuit that will work, I would be very appreciative.

Thank you
Rodney W3LDR
Amateur Radio Operator

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The simplest design I have seen from a reputable technical source was to use a ~300W step-up transformer with large variac on 120Vac/60Hz input. Large 100 watt resistors were used to current limit when the water conductivity increases significantly. Not sure how much of the power was used or R values.

I supposed a 40~100W light bulb in series might work well as a constant current limiter with <10: 1 dynamic resistance, to eliminate the variac.

four nines silver (99.99) 2mm wire with Sodium free de-ionized water was used !

The process took 15 minutes and water was only slightly discolored but sparkly under laser pointer.

An important aspect was the resonance of waves on the surface by placing the wires equidistance from walls and wire or 1/3 spacing across the top.
This provided the optimal wave effect as the water wicks up the wires ( with a 1cm radius) at least ~2 cm from the water surface.
Container was just a foodgrade plastic tub, like a 1kg margarine container which gives good insulation.

The water was almost tasteless sort of like Perrier water with some tangible sensations

It is interesting to note that Johnson & Johnson has the patent for colloidal silver coated bandaids and most Doctor's offices here have silver coated cotton tipped sticks (Q tips) for cleansing as pure silver particles have some localized antibiotic effects.

But certainly like most things in excess, silver can be poisonous and cause damage.

I know others who make colloidal water of all precious metals, but don't have the technical background but do have steady business with homepathic doctors.

Quality control is very important as is the sodium free de-ionized water and impurity level in silver.

I cannot verify the efficacy of CS but there are many who do.

Also effective are He/Ne/Ar plasma tubes (1cm *20cm) excited with 21MHz modulated pulses according to certain frequency patterns( using any license free band). This technical specialist had his own invention, production line and cured his cat from cancer (diagnosed and verified by his Vet.)