"Stewart Pinkerton" wrote in message

On Thu, 11 Nov 2004 16:08:44 GMT, (Don
Pearce) wrote:

The thermionic valve is one hundred years old this week.

That depends on who you believe invented it..............

If you attribute it to Guthrie than its 100th anniversary was in 1973. If
you attribute to Edison, then it was 100 years old in 1880. If you attribute
it to Richardson who won a Nobel prize related to it, then you've got about
19 years to go.

Fleming patented his related discovery the diode, in 1904.