| abstract |
A digital display type tachometer for an automobile for numerically displaying a rotation speed of the engine comprises a numeric character display device having display sections for 1000's, 100's, 10's and 1's digits, the 1's digit display section being constructed to display always "0", a counter for counting pulses generated in synchronism with the rotations of the engine to produce a BCD signal depending on the rotation speed, and decoding/driver means for decoding the BCD signal into decimal numeric character signals for 1000's, 100's and 10's digits and driving the 1000's, 100's, and 10's digit display sections by these character signals, respectively. The digital display type tachometer further comprises means for detecting whether the rotation speed of the engine is higher than 1000 rpm and producing a detection signal when the rotation speed is higher than 1000 rpm and means for controlling in response to said detection signal the 10's digit display section to display "0", whereby when the rotation speed of the engine is higher than 1000 rpm the rotation speed of the engine is displayed only with 1000's and 100's digits, while when the rotation speed of the engine is lower than 1000 rpm, the rotation speed is displayed with 100's and 10's digits. |