| 摘要 |
<p>Appts. detecting mineral deposits underground uses an array of electrodes and driving circuits recording voltage against current characteristics of a tract of ground. The press. of certain mineral deposits can be deduced from this kind of recorded information. Noise and electro-chemical polarisation effects are compensated for. Two sets of electrodes are sunk in the ground. A current source, amplifier, and rectifier supply a current to the electrodes and this current is changed according to a programme. Two voltage measurement electrodes are situated between the current drive electrodes and these supply signals to a difference amplifier. The current and detected voltage are both fed to an XY recorder on which the full characteristic of a tract of ground is recorded.</p> |
