Figure 8.2 Heater Connections Indicated By Removing the Heater From the Tube Symbol. On the left there is a transformer and two tubes as in Figure 8.1. But this time the triode is a dual triode such as a twelve A X seven. V2 is a pentode such as a six V six G T. The tube symbols do not have heaters included. The heater symbols are now with the transformer. The heater winding of the transformer is labeled 6.3 V A C. The top of the winding goes to pin 9 and the bottom of the winding goes to pins 4 and 5 of V1. This connects the two heaters in parallel across the 6.3 volt winding and the heater symbols are shown connected in parallel. The top of the winding connects to pin 2 and the lower end to pin 7 of V2. On the right there is also a transformer with a heater winding labeled 12.6 V A C. V1 is the same as on the left. V2 is a pentode such as a twelve L six G T. The top of the heater winding connects to pin 4 and the bottom to pin 5 of V1. This connects the two heaters in series across the 12.6 volt winding. The top of the winding connects to pin 2 and the bottom to pin 7 of V2. Many times on actual schematics the tube symbols will include heater symbols but they will not be connected to anything. Elsewhere on the schematic, always near the power transformer all of the heaters will be shown as in Figure two. End verbal description.
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