Power Darlingtons

Figure 6.16 Circuit symbol for a two-junction transistor or power Darlington...

Stockton and Darlington Railway completed, first public steam powered railway. 

The Darlington Nuclear Generating Station is located 70 km east of Toronto. It uses a fuel of natural uranium to produce enough electricity to provide power for a city the size of Toronto. 

One problem, or should we say challenge, in designing this type of circuit is to ensure that the Darlington pair transistors are not overstressed by causing them to dissipate too much power. The maximum power the transistor can dissipate decreases with increasing collector-emitter voltage. 

W.B. Darlington, Activated Cathodes for Reduced Power Consumption in Electrolytic Cells, In O. DeNora (ed.). Proceedings of the DeNora Symposium on Chlorine Technology., Venice, (1979), p. 30. E. Nicholas, Fr. Appl. 7917441(1979). 

The designer must check the power dissipated by the pass transistor (the Darlington transistor) to determine the heat sinking requirements. 

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