Input: Read this: Modern electrification systems take AC energy from a power grid which is delivered to a locomotive and converted to a DC voltage to be used by traction motors. These motors may either be DC motors which directly use the DC or they may be 3-phase AC motors which require further conversion of the DC to 3-phase AC (using power electronics). Thus both systems are faced with the same task: converting and transporting high-voltage AC from the power grid to low-voltage DC in the locomotive. Where should this conversion take place and at what voltage and current (AC or DC) should the power flow to the locomotive? And how does all this relate to energy-efficiency? Both the transmission and conversion of electric energy involve losses: ohmic losses in wires and power electronics, magnetic field losses in transformers and smoothing reactors (inductors). Power conversion for a DC system takes place mainly in a railway substation where large, heavy, and more efficient hardware can be used as compared to an AC system where conversion takes place aboard the locomotive where space is limited and losses are significantly higher. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for.
Question: Modern electrification systems take DC energy from what?

Output: unanswerable

Input: Read this: With Yoritomo firmly established, the bakufu system that would govern Japan for the next seven centuries was in place. He appointed military governors, or daimyos, to rule over the provinces, and stewards, or jito to supervise public and private estates. Yoritomo then turned his attention to the elimination of the powerful Fujiwara family, which sheltered his rebellious brother Yoshitsune. Three years later, he was appointed shogun in Kyoto. One year before his death in 1199, Yoritomo expelled the teenage emperor Go-Toba from the throne. Two of Go-Toba's sons succeeded him, but they would also be removed by Yoritomo's successors to the shogunate.
Question: Who strengthened the Fujiwara family during their rule?

Output: unanswerable

Input: Read this: After 1857, the colonial government strengthened and expanded its infrastructure via the court system, legal procedures, and statutes. The Indian Penal Code came into being. In education, Thomas Babington Macaulay had made schooling a priority for the Raj in his famous minute of February 1835 and succeeded in implementing the use of English as the medium of instruction. By 1890 some 60,000 Indians had matriculated. The Indian economy grew at about 1% per year from 1880 to 1920, and the population also grew at 1%. However, from 1910s Indian private industry began to grow significantly. India built a modern railway system in the late 19th century which was the fourth largest in the world. The British Raj invested heavily in infrastructure, including canals and irrigation systems in addition to railways, telegraphy, roads and ports. However, historians have been bitterly divided on issues of economic history, with the Nationalist school arguing that India was poorer at the end of British rule than at the beginning and that impoverishment occurred because of the British.
Question: What did the Colonial government expand by legal means?

Output: infrastructure

Input: Read this: Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated.
Question: How much current is needed to saturate a light-switch?

Output:
unanswerable