Abstract: A self-regulating heater including a semiconductor for converting electrical energy to heat. A temperature sensitive element is used to bias the semiconductor as a function of temperature. The heating element has an advantage that its maximum temperature is limited by the biasing network, yet full power is available just below the limit.

Abstract: A method and apparatus for automatically dispensing cash and performing other transactions relating to customer accounts. A magnetic card reader reads coded information into the system from a credit card which information identifies the account of the user. A keyboard entered code is compared with the card encoded information to verify that the account is that of an authorized user. The system includes a disc storage file which is checked for the account numbers of stolen cards and of accounts with respect to which transactions are to be restricted or otherwise modified. The file also includes a list of the images of cards read in the most recent past transactions and against these images the inserted card is checked for detection of duplicate cards. The system is capable of performing different types of transactions involving plural accounts of each user. A control code on each card enables the selection of only those machine functions which the user is authorized to select.