Abstract: A tape recorder is described which is substantially fully integrated and which performs the required functions of a tape recorder in either the recording or playback mode. The tape recorder is readily converted from the record to the play mode of operation by simple switching means which operate to control selected current sources on the integrated circuit to activate or inactivate the functional blocks of the integrated circuit involved in the selected mode of operation. By the use of a temperature compensated reference in the emitter path of a differentially connected transistor pair to stabilize the current in two current mirrors not simultaneously operated, one may stabilize current sources associated with either mirror. The arrangement thus permits a highly economical method of mode control while at the same time preserving high temperature stability in all of the controlled functional elements.

Abstract: The present invention relates to a numerical display having a reduced dc current requirement per character display site. The invention is applicable to a variety of numerical displays including seven segment and 4.times.7 matrix displays using light emitting diodes, and low voltage incandescent segmented units designed to replace light emitting diode displays. A practical application is for displaying time in an ac powered clock or clock radio in which it is desirable to keep the dc current requirement of the display to a substantially constant minimum suitable for use with a low cost, transformerless power supply conventional with radio receivers. The current requirement of a character display site is reduced over that of full parallel operation by selectively serializing certain light sources in a manner leaving the display control circuitry uncomplicated by permitting each light source state to be controlled by a shunt control switch sharing a common bus. Since a seven segment display may assume 2.sup.

Abstract: The present invention relates to a numerical display having a reduced dc current requirement per character display site. The invention is applicable to a variety of numerical displays including seven segment and 4.times.7 matrix displays using light emitting diodes, and low voltage incandescent segmented units designed to replace light emitting diode displays. A practical application is for displaying time in an ac powered clock or clock radio in which it is desirable to keep the dc current requirement of the display to a substantially constant minimum suitable for use with a low cost, transformerless power supply conventional with radio receivers. The current requirement of a character display site is reduced over that of full parallel operation by selectively serializing certain light sources in a manner leaving the display control circuitry uncomplicated by permitting each light source state to be controlled by a shunt control switch sharing a common bus. Since a seven segment display may assume 2.sup.