(Creating the Circuit) How the Instrument Works
How a locating instrument works can be summarized by six statements…
1. There are only two ways to receive: peak and null.
2. There are only two ways to transmit: metal-to-metal and non-metal-to-metal.
3. Signal wants to leave equally in all directions.
4. Signal always follows the path of least resistance.
5. Different frequencies can and sometimes will do certain things.
6. You can’t change the results of a locate with the receiver.
There are five ways to check the shape of the field: peak versus null, digital depth validation, the straddle test, the lift test and triangulation (Figures 30-34).
The level of current is determined by looking at the peak number. The peak number will either be steady, fluctuating some or fluctuating a lot. Depending on the peak number’s fluctuation or lack of it, we term the level of current as being good, OK or poor current.