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![]() On 8-May-2004, "Jack Painter" wrote: experiment) from keeping all of that available voltage (0v felt on neutral) as long as the current did not exceed 15a or whatever your breaker allows. Obviously a 100w light bulb shorted to ground would blow instantly, before the breaker could protect it.. Uhhhh, No! The most voltage from either wire of a 117 Volt household circuit to any other wire or to any made ground is 117 Volts. The light bulb would be quite happy to glow at something up to its normal brightness for as long as you wanted. Now if the grounded conductor was somewhere out in a field instead of being the local house ground, then the light bulb would not receive the full 117 Volts, because of the resistance of the intervening earth, and would be unhappily dim. As for the Original Poster's question about the 117N7 transmitter, they were inherently unsafe unless built on a chassis insulated from the antenna and ground. The usual method was to use a floating negative (not connected to the metal chassis) inside the transmitter. The antenna was isolated from the 117 VAC circuit by the DC blocking capacitor to the pi network. The external antenna ground connected to the chassis. The cathode of the tube and the negative side of the DC Power Supply had to be bypassed to the chassis through a large capacitor for an RF ground. In no case should the neutral conductor be left unconnected, even if a water pipe ground could carry the neutral current. That would leave 117 VAC on the chassis (and the metal shafts of tuning capacitors.. and the ON/OFF toggle switch) if the ground wire came loose. I grew up in that era too and got many shocks from AC-DC radios. Ken Fowler |
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