Last revised: October 28, 2024
Reviewed by: Scott Orlosky, consulting engineer

Digital timers are used to trigger an action, to start timing once triggered by an action, or both. Some products are programmable while others may be fixed at a set internal time and function. In addition to the number and type of functions, these devices differ in terms of time range settings.

Types

Suppliers of digital timers offer meter, delay-on, delay-off, one-shot, recycle, and interval delay timers.

• Timer meters, indicators, or totalizers are used in applications for display of elapsed process time or tracking running time of factory machinery.
• Delay-on timers require a predetermined period of time to pass between when the timer receives its input signal and when the output is energized. At the end of the time delay, the contacts open or close. If the contact is normally open (NO), then the load energizes at the end of the time delay. If the contact is normally closed (NC), then the load de-energizes after the time delay. Removing power resets the time delay and output. This capability is also called on-delay, delay on make, delay-on operate, operate delay, pre-purge delay, and delay-on energization.
• Delay-off timers start their timing functions when the power supply is interrupted. When the power is initially supplied, the output relay contacts react immediately. When the power supply is removed, the output relay contacts remain in the activated position and the time period starts. When the time has elapsed, the output relay contacts release. This capability is also called delay on release, delay on break, release delay, post-purge delay, and delay on de-energization.
• One shot timers are designed so that when power is applied to the timer, the contacts change position immediately and remain changed for the set period of time after the timer has received power. After the set period of time has passed, the contacts return to their normal position. These devices are also called pulse formers.
• Interval delay timers are the opposite of delay-on devices in that the relay is energized immediately upon application of the supply or closure of the switch input, and goes off at the end of the period.  Interval delay is sometimes called delay pulse.
• Recycle timers act so that the closing of the control switch starts the cycling function. The load continues to turn ON and OFF at regular time intervals as long as the control switch is closed. The cycling function stops when the control switch is open. This function is sometimes called a flasher, or pulse generator.

Other important functions of digital timers include delay cycles, position indicators, preset counters, arithmetic functions, controllers, and counter and timer combinations.

Applications

Digital timers have both common consumer uses and large industrial uses. Timers are used in process control equipment to assist in process regulation, they are installed in industrial equipment to record its use and age, and they are used as consumer electronics for household use and recreational use.

Digital Timer FAQs

How do digital timers differ from traditional mechanical timers in terms of accuracy and functionality?

Digital timers are generally more accurate than mechanical timers. They can perform precise timing functions and are less susceptible to variations caused by environmental factors such as temperature, vibration, and shock.

Mechanical timers rely on physical mechanisms, which can introduce inaccuracies due to wear and tear, friction, and environmental conditions. They are typically less precise compared to digital timers.

Digital timers offer a wide range of functions, including delay cycles, position indicators, preset counters, arithmetic functions, controllers, and counter and timer combinations.

They can be programmed using various interfaces such as keypads, pushbuttons, and dials.

Digital timers are used in both consumer electronics and industrial equipment for process control, regulation, and recording usage and age.

Mechanical timers typically include features like combined counter/timer mechanisms, audible alarms, and dial indicators. They are often used in sequential, automatic control applications.

Mechanical timers can be designed to be compact, rugged, and resistant to environmental factors. They are commonly used in applications such as automatic milling machines, periodic lubrication, and industrial washing machines.

How do electromechanical timers compare to digital and mechanical timers?

Electromechanical timers combine elements of both mechanical and digital timers, offering a unique set of features and functionalities.

Digital timers are generally more accurate than mechanical timers. They perform precise timing functions and are less susceptible to variations caused by environmental factors such as temperature, vibration, and shock.

Mechanical timers rely on physical mechanisms, which can introduce inaccuracies due to wear and tear, friction, and environmental conditions. They are typically less precise compared to digital timers.

Electromechanical timers can be set up or programmed to perform one or more functions and differ in terms of accuracy and repeatability. They have both minimum and maximum time intervals and can be configured for multiple ranges or are field-selectable.

Digital timers offer a wide range of functions, including delay cycles, position indicators, preset counters, arithmetic functions, controllers, and counter and timer combinations.

They can be programmed using various interfaces such as keypads, pushbuttons, and dials They are used in both consumer electronics and industrial equipment for process control, regulation, and recording usage and age.

Mechanical timers typically include features like combined counter/timer mechanisms, audible alarms, and dial indicators. Often used in sequential, automatic control applications.

These timers can be designed to be compact, rugged, and resistant to environmental factors. Commonly used in applications such as automatic milling machines, periodic lubrication, and industrial washing machines.

Electromechanical timers can accept a voltage, current, frequency, or pulse as an input, and can send serial, digital, or switch outputs. Programming options often include knobs, dials, keypads, and pushbuttons.

They may be rated as explosion-proof or include audible alarms and visual signals and they are typically used in factories and other industrial settings. For example, they may cause a valve to open and remain open for a specified period of time, or cause a mixer to turn on and remain running upon receiving a signal that more mix has been added.

What are the specific programming options available for digital timers?

Digital timers roughly fall into categories dependent on the function they need to perform and/or how they are activated. That being said, there are often a variety of ways to perform a timing function. Here are common uses and features of digital timers.

Interfaces for programming

• Keypads: Users can input settings and parameters directly using a keypad interface.
• Pushbuttons: Simple pushbuttons allow for easy adjustments and settings.
• Dials: Rotary dials can be used to set time intervals and other parameters 

Functions and features:

• Delay cycles: Digital timers can be programmed to delay the start or end of a cycle.
• Position indicators: These timers can indicate the position within a cycle or process.
• Preset counters: Users can set specific counts that the timer will track and act upon.
• Arithmetic functions: Some digital timers can perform basic arithmetic operations to aid in complex timing functions.
• Controllers: Digital timers can act as controllers in a system, managing various processes.
• Counter and timer combinations: They can combine counting and timing functions for more versatile applications.

What is the role of digital timers in consumer electronics?

Digital timers provide precise and versatile timing functions that enhance the functionality of various devices. Here are some examples.

Digital timers are commonly found in kitchen appliances such as ovens, microwaves, and coffee makers. They allow users to set precise cooking or brewing times, ensuring consistent results.

Thermostats and HVAC systems often use digital timers to regulate heating and cooling cycles, improving energy efficiency and comfort.

Digital timers are used in lighting systems to automate the turning on and off of lights, which can enhance security and save energy.

Treadmills, exercise bikes, and other fitness equipment use digital timers to track workout durations and intervals, helping users manage their exercise routines effectively.

Digital timers can be found in audio and video equipment, allowing users to schedule recordings or automate the operation of devices.

Many electric toothbrushes incorporate digital timers to ensure users brush for the recommended duration.

Devices such as facial steamers and hair removal tools use digital timers to control treatment durations, ensuring safety and effectiveness.

Digital timers are used in security systems to automate the activation of alarms and surveillance equipment at specific times.

Many consumer electronics include digital timers that automatically shut off the device after a set period, enhancing safety and conserving energy.

Digital Timer Media Gallery

References

GlobalSpec—Mechanical Timers

GlobalSpec—Electromechanical Timers