For my unit, the whole circuit consists of one component, a transformer 
with just 2 windings, each with 2 wires. connect 120 VAC to one winding 
pair of wires, the other winding gets connected one wire to a ground rod 
(I use a 2 foot long 1/2" EMT thinwall electrical conduit), and the 
other to the fence wire. The fence wire has only that one connection. 
The circuit is completed when the animal touches both the ground (earth) 
and fence wire at the same time.

Some other fence controllers (power supplies) have electronics and DO 
pulse, but not my cheap model.

Sean Breheny wrote:
> The site mentions "pulses" so perhaps they are doing something more
> than just sinusoidal AC. Just because your DMM reads 440-660 on the
> normal VAC scale doesn't tell you what the waveform is like.
>
> Sean
>
> On 5/29/07, Jinx <joecolquitt@clear.net.nz> wrote:
>   
>>> I have a farm type electric fence power supply that we use to keep
>>> critters (deer, raccoons, etc.) out of our vegetable garden. It is 120
>>> VAC 10 watt max input, and output is 440 - 660 VAC measured
>>> with a DMM
>>>       
>> Isn't that really dangerous ? An electric fence is normally, IME, a
>> pulsed affair, not constant high voltage. Do you hear any interference,
>> like clicking, on an AM radio for example ?
>>
>> If it interests you, I have a commercial "hot fence" indicator. It's based
>> on a 74HC04, powered by a coin cell. You hang it on the fence. There
>> is no electrical contact. The HV pulse triggers the 74HC04 to blink a
>> LED
>>
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