timer
When Timer (Engl. For timer) or timer in the narrow sense is called in technical computer science and electronics a control module, which for the realization of different time-related functions as well as in meters is used.
In a broader sense, the word timer for sleep timer , timers , timer , timing relays and electronic circuits or circuits as well as for internal function used in microcontrollers. Such internal controller structures represent one or more different timers that can be operated independently of one another.
Possible areas of application include a. Pulse generators , clock generators , for time measurement or reference timers for event counters.
Timers can be implemented as software or as hardware (electronic circuit). Both variants require a time standard or timing element . Software solutions use the clock frequency of the microcontroller for this. The clock frequency is determined by a quartz oscillator , a piezo oscillator or a timing element in the integrated circuit. Electronic circuits or timer circuits use an external timing element ( RC element made of resistor and capacitor ).
The internal signal delay time of electronic circuits can also be used as a time delay.
In the nanosecond range, timing elements are designed as lines of a certain length, but are usually not referred to as timers.
Often timer circuits also contain programmable frequency dividers , so that not only times in the range from microseconds to milliseconds, but up to several hours or days can be realized.
See also
- Real time clock
- Clock signal
- time stamp
- Function generator
- Digital stopwatch
- NE555 , 74HC123 (PDF; 296 kB), CD4538 (timer circuits; PDF; 141 kB), CD4541 (programmable timer circuit ; PDF; 254 kB)
Web links
- Switchable times with transistors
- Timer for long times with the famous LMC555 timer IC
- Long-term timer circuits with the frequency dividers CD4020B and CD4040B