Nikola Tesla Books
Books written by or about Nikola Tesla
Colorado Springs
July 22, 1899
Further modes of connecting apparatus with two sensitive devices for telegraphy and such purposes. A connection as in sketch showed quite satisfactory results. The sensitiveness was probably due to the fact that the secondary was open as in a previous instance. Several plans of working with two or more devices in multiple were experimented with. The idea was to introduce greater regularity and reduce resistance of the path through the sensitive apparatus.
Some arrangements worked well, for instance the one illustrated in sketch 2. In 3. both devices a and a1 were shunted by a high self-induction L, the inductive and ohmic resistance of which was regulated so that devices a a1 would break down at the slightest disturbance. The results were fair but not better than before obtained with other dispositions. The relay was placed in a number of ways, best results when it was in the secondary S.
In Diagram 4. the same mode of connection was employed, only a battery and relay were placed in the bridge. The employment of the special battery B1 allowed some adjustments to be made not practicable in Diagram 3. Generally, battery B1 was differentially connected with respect to battery B.
96
July 22
Figure 8 shows the circuit of a receiver obtained by modification of the transmitter Tesla was then experimenting with. When functioning as a transmitter it is powered from the mains and is in fact a standard Tesla oscillator with a mercury interrupter between the condenser C and the primary P. The relay, sensitive device a1 and battery B1 are omitted and the secondary is connected to the antenna and ground. It may be noted that Tesla did not use the best receiver modification (as in Fig. 6), probably to simplify reconnection as a transmitter.
July 22
With the same elements as on the previous day he continues the experiments witli the receiver. He looks for merthods to reduce the resistance for currents through sensitive devices, and to increase the operation regularity. In Fig. 4, he introduces the schematic in the shape of a bridge with battery, relay and transformer secondary in the diagonal Fig. 8 represents the receiver schematic which is obtained by connecting the transmitter with which he experiments. When this device operates as a transmitter, it is supplied from the network and becomes the classic Tesla's oscillator with mercury breaker between capacitor C and primary P. Then the relay, sensitive device a1 and battery B1 are disconnected. The secondary is connected to antenna and the ground. As can be seen, in the combination of the same device as receiver, he does not use the best combination (as in Fig. G), probably due to simplicity of reconnection from transmitter to receiver.
