There is another reason why tantalum capacitors are currently in demand. This is the fact that this component is most effective in resolving the issue of power source consistency.
As is widely known, the operation of semiconductors is becoming increasingly high speed and in recent years the operating frequency has begun to shift from the 1GHz (giga hertz) range to the 3GHz or more range.
An operating frequency of 1GHz means that in switching from 0 to 1, the voltage must increase from 0 volts to the required voltage in 1 nano second, or an astonishingly short one billionth of a second, in order for the semiconductor to operate normally.
On the other hand, electronic equipment as represented by personal computers reduce the high voltage from home power source or batteries to between 1 to 3 volts that a semiconductor is capable of utilizing and for this reason, utilize power source circuits called power source converters or switching power source.
However, the operating speed of a power source circuit is a few micro seconds even for the fastest circuit.
In other words, merely directly connecting the power source to the semiconductor results in the phenomenon of the power source being unable to supply power when the semiconductor attempts quickly to switch from 0 to 1.
In fact, this issue has been identified as the main cause of occurrence of noise that is a major problem in recent years. According to detailed experiments, an astounding 90% of noise that occurs in electronic equipment is caused by the inconsistency of the timing with which power is supplied to the equipment.
From empirical results, it has always been claimed that tantalum capacitors are effective in limiting noise and this is understandable when viewed from the perspective of the issue of electricity supply.
In other words, if the supply of electricity is represented as tap water supply, the switching power source would be the water reservoir located upstream in the river. On the other hand, the capacitor would be the water tank installed at condominiums and other structures.
In the hottest summer months, for example, when the residents of the condominium simultaneously use tap water, were the supply of water to be controlled by the opening or closing of the water reservoir, there is no way that the system could keep up with the downstream needs. However, if there is a water storage tank at the condominium, required water may be supplied quickly and there is no danger that the water pressure will decrease thus causing disruption in the water supply.
In the same way, capacitors speedily supply electricity when semiconductors require power and act to fill the approximately 10 micro second gap required for the power source to catch up with the semiconductor's requirement.
From this perspective, the capacitors of the future need not only to have a large capacity but must also have low internal resistance in order to be able speedily to discharge electricity when required.