Cmos, "Two Electric Fence Monitors"
Created: "April 3, 2010" Updated: "June 29, 2015"These circuits are designed to detect the Status and Strength of an Electric Fence.
NOTE: This has Only been Tested on My Car Coil Fencers. I do NOT Know How good it will work on Lower Voltage, Commerical made Fencers.
This is a Very Simple and Efficient Design giving a visable indication on an LED. There is No Direct Connection to the actual Fence or HV System.
They detect the Radiated signal coming through the air and depending on the Pulse rate of your fence, it draws a very small average Current from the battery or supply.
They may be Powered by a 9 Volt battery as a portable device. Both draw about 2.7 mA without the LED lit and 13.3 mA when the LED Lights up. Or they can be operated from the 12 Volt supply of your Electric Fence as a permanent monitor, Assuming the supply is a good 12 volt battery or a well filtered DC source.
Operating this device on a 9 volt battery, in my hand and without a earth ground,
it detects the pulses from my fence at over 4 feet.
(My fence is only 4 to 5 inches above ground and its somewhat stronger than most.)
By Operating this device in a portable fashion, and slowly moving away from the fence
it should give a comparative reading on the strength of your High Voltage Pulses.
A Definate PLUS for checking Losses in your Insulators.
NEW: C-Mos Version-2 of this device, Also now are available. It features the LED, as well as a (Aprox 1000Hz) Audio Tone via a Pizo transducer. It draws the same current as Verson-1 and works very good.
The length of the audio Tone has been increased compared to the actual pulse, so it is much more easy to hear. (Otherwise on the short pulses it would just be a quick "Click" sound and very hard to hear.)
Kits of parts/pcb are available from me.
"Version 1, Schematic"
"Version 2, REVISED Picture overlay".
"Version 2, Picture of Connections".
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Chemelec
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