Page 489 echo sounding 5266 



IV. Functional switches — Continued. 



B. Starting and frequency-selector switch — connecting 



33. (L) plate of 13 to 34 or grid of 14. 



34. (R) grid circuit of 17.5-kc oscillator (55) to ground or to 33. 



35. (L) common grid circuit of 18, 19, and 20 to sonic (53) or supersonic (51) 



amplifier. 



36. (R) plate of 14 to sonic keying relay (60). (Caution 1,000 volts!) 



37. (L) 110 volts, 60 cycles to indicator starting motor. 



38. (R) 110 volts, 60 cycles to Fathometer supply line relay. 



39. (L) gain-control rheostat to supersonic amplifier. 



40. (R) phone jack to supersonic-amplifier audio channel (52), or to sonic-amplifier 



audio output (54). 



41. (L) 110 volts d-c to starting relay for 525-cycle motor generator (58). 



42. (R) polarizing current source (24) to hydrophone. 



V. Motors. 



A. For starting. 



43. 110-volt 60-cycle motor. 



44. push-button switch. 



45. autotransformer. 



46. 4-microfarad condenser. 



B. For synchronizing. 



47. 1025-cycle non-selfstarting synchronous motor, 



48. 1025-cycle tuning fork (in power-supply rack). 



49. thermionic-tube tuning-fork circuit (in power-supply rack). 



50. 1025-cycle power-amplifier circuit (in power-supply rack). 



Echo Amplifier 



I. Supersonic. 



51. 17.5-kc amplifier. 



52. audio-channel phone output. 



II. Sonic. 



53. 1050-cycle amplifier. 



54. audio phone outlet. 



Power Supply 



I. Supersonic. 



55. 17.5-kc vacuum-tube oscillator (type 59 tube). 



56. 17.5-kc power amplifiers (types 807 and 838 tubes). 



57. high-voltage d-c rectifier circuit and time-delay relay. 

 IT. Sonic. 



58. 525-cycle motor generator. 



59. speed (frequency) control adjustment for 58 and frequency meter. 



60. keying relay. 



Acoustic Units 

 f. Supersonic. 



61. transceiver. 



62. circuit furnishing polarizing current to 61. 



II. Sonic. 



63. type 324 electromagnetic oscillators. 



64. hydrophones. 



Power Source 



65. turbogenerator or rotary converter. 



66. ship's 110-volt direct current. 



67. 110-volt 60-cycle for 53 (if d-c is not used). 



