????? ???? ?? ?? ?? ???? ?? ???? ??? ? ????? ???? ???????? ?? ??? ???? ??? ????? ?? ????.Hewlett and Packard's 1st fiscally prosperous merchandise was a precision audio oscillator generally known as the HP 200A, which made use of a little incandescent mild bulb (often known as a "pilot light") as a temperature dependent resistor inside of a importa