SEIDEL and KLIMA: CRITERIA FOR ELECTRICAL HARVESTING 



Figure 1. — Pulse generator output pulse matched into the load resistance A - low, B - 



compensating pulse are shown in D. 



high, C - correctly; the output pulse and 



amount of electrical energy is contained within 

 the envelope of the compensating pulse as is 

 within the main pulse except the compensating 

 pulse is of an opposite polarity. The compensating 

 pulse has no effect on fish reaction, since its 

 amplitude is many times less than the main pulse 

 and is below the threshold level of the fish. 



The electrode array and pulse generator were 

 designed to effectively energize a minimum 

 volume of water at least 2 m in cross section 

 and 4 m long, and provide a selection of minimum 

 electrical field concentration from 15 to 30 V/m. 

 Each electrode of the array consisted of a copper 

 tube frame with copper strips arranged in a grid 

 pattern. The strips of copper were 15.2 cm wide 

 (6 inches) with square grid openings of 45.7 cm 

 (18 inches) between strips. It has been experi- 

 mentally demonstrated that the surface of an 

 electrode can be reduced to approximately 10% 

 of the total area and the surface will function 



electrically as if it were a solid plate (C. Kreutzer,'* 

 pers. commun.). Our electrode design reduced the 

 conducting surface of the electrode to approxi- 

 mately 53% of the total area. Therefore, this grid 

 technique was utilized to allow the fish to be led 

 to and pass through the anode for easier evalua- 

 tion of their response. The cable connecting the 

 electrode array to the pulse generator was a 12-m 

 length of 1/0 coaxial conducting cable and repre- 

 sented a total resistance of approximately 0.01 

 ohm, or a total power loss of 20% in an overall 

 array resistance of 0.05 ohm. Coaxial cable was 

 utilized to eliminate pulse distortion and losses 

 caused by inductance in parallel conductors. 



Field strengths listed in volts per meter are 

 averages based on measured electrode-to-elec- 

 trode values and separation distance between 

 electrodes rather than an in situ field strength 



"Smith Research and Development Company, Lewes, Del. 



659 



