Rheostat. an electric device for controlling and limiting current or voltage in an electric circuit. The principal component of a rheostat is a conducting element with variable resistance.The magnitude of this resistance may be varied smoothly or in discrete steps.heostat. an electric device for controlling and limiting current or voltage in an electric circuit. The principal component of a rheostat is a conducting element with variable resistance. The magnitude of this resistance may be varied smoothly or in discrete steps.
troy ounce: $992.00: $990.00: Rhodium : Rh : troy ounce: $1860.00: $1860.00: Iridium : Ir : troy ounce: $990.00: $990.00: Ruthenium : Ru : troy ounce: $200.00: $200.00: Osmium : Os : troy ounce : $400.00: Rhenium : Re : pound : $1290.00: Gold : Au : troy ounce : $1323.90: Silver : Ag : troy ounce : $16.450 : Last update:
Only about 25 tons of rhodium are mined each year. Compare that to the 2,350 tonnes of gold mined in 2009, or the 220 tons of platinum mined each year... With such a limited supply, rhodium doesn't come cheap. It is the most expensive of all precious metals, currently trading at $2,725 an ounce. (To give you a better idea of its cost, that's over twice as expensive as gold and 154 times more than silver.) The spot prices of rhodium are set by Johnson Matthey twice daily for the American market.