Hi all,
I'm building a resistivity meter. For those not familiar, you pump electricity into the ground and measure the reisitance of the soil with probes. It is supposed to allow you to identify objects/materials below the surface based on how much electricity they retain. It works by comparing the electricity sent out by the anode and the electricity gathered by the recieving probes through a simple op amp.
I started with a 12V battery hooked to an engine alternator and a 5000 w 120v inverter. Hoping to get +30A of power coming from this.
The design I'm using(see attached) is a manual style, where the anode line running 30a goes through a potentiometer before splitting to an op amp, where the op amp feeds back to the potentiometer for "zeroing out" and the other feeds to the op amp coming from the reciever probes.
My problem is that with that much power flowing through the anode, I'm having trouble finding affordable components. The potentiometers and op amps are hundreds of dollars each.
i'm wondering if I can cut way down on the power with a resistor before going to the potentiometer. this will affect he performance of the op amp, but I'm not sure how.
Is there anyone out there that really understands op amps and can tell me what configuration I need and what components to either handle this amount of power or go around it with the op amp still working?
I'm building a resistivity meter. For those not familiar, you pump electricity into the ground and measure the reisitance of the soil with probes. It is supposed to allow you to identify objects/materials below the surface based on how much electricity they retain. It works by comparing the electricity sent out by the anode and the electricity gathered by the recieving probes through a simple op amp.
I started with a 12V battery hooked to an engine alternator and a 5000 w 120v inverter. Hoping to get +30A of power coming from this.
The design I'm using(see attached) is a manual style, where the anode line running 30a goes through a potentiometer before splitting to an op amp, where the op amp feeds back to the potentiometer for "zeroing out" and the other feeds to the op amp coming from the reciever probes.
My problem is that with that much power flowing through the anode, I'm having trouble finding affordable components. The potentiometers and op amps are hundreds of dollars each.
i'm wondering if I can cut way down on the power with a resistor before going to the potentiometer. this will affect he performance of the op amp, but I'm not sure how.
Is there anyone out there that really understands op amps and can tell me what configuration I need and what components to either handle this amount of power or go around it with the op amp still working?
