Electronic Timers: How Does It Work?

by Brad Welch

Electronic Timer Basics

Although Omron digital timers exist in many different ways, quartz timers are comparatively cheaper and far more accurate than other methods, they have become the standard. Within quartz timers are computers and a range of other devices in microwaves.

Piezoelectric Quartz

Crystal quartz has a beneficial trait, called piezoelectricity. When an electric current is provided by a quartz crystal the crystal bends. When the crystal pops back a tiny amount of energy is released. It effectively reverses depending on the scale and nature of the quartz crystal curves.

The Oscillator

At the heart of an electronic timer is a very small, precise, quartz crystal designed for vibrating at a certain frequency. If the crystal constantly twists and swings, a spinning current is set — an electrical current that rises and decreases in normal waves. The electrical current oscillates at a steady rate, when precisely the quartz crystal is split.

Using the Oscillator

The electronic timer circuit tracks the pulses of the oscillator and activates these actions when there are multiple pulses in it. For example, a time circuit in a watch tracks the pulses before passing a second, then sends out a signal and reboots the count. Then, a second portion of the circuit records seconds, and then minutes via the clock. Signals may be transmitted via timers to other devices, too. For example, if a timer for a burglar alarm is placed in the door lock before  activating the alarm system and calling the security service, someone may give the alarm to deactivate for 20 seconds.

What Is Quartz Movement in Watches?

Many watches have a quartz mechanism which provides extremely accurate timekeeping at low cost. Quartz crystals, which are characteristic of many electronic devices, enable for accurate time calculation under different conditions. The battery of most quartz movement reloads will last years, due to the crystal’s energy efficiency.

Theory of Operation

A continuous number of pulses are emitted by the quartz crystal at a rate of 32,768 per second (Hz). An electronic circuit controls this stream of pulses, and each pulse is produced by a single pulsed pulse. This new pulse is now one pulse per second which reflects the clock’s time limit. The screen notifications every second.

Quartz Crystal

A quartz crystal is a tiny piece of silicone dioxide which is either made or naturally formed. This crystal with defined physical characteristics is of a specific dimension and orientation. Silicone-dioxide is piezo-ionic, meaning it vibrates at exposed electrical voltage. The sensation is very steady due to variations in temperature, which relies on crystal cutting.

Oscillator Circuit

When a quartz crystal is connected to the oscillator circuit, a steady flux of pulses is generated, based on the frequency. A frequency of 32,768 kHz is common for a watch. An oscillator circuit powered by a battery that provides a constant frequency output regardless of temperature, voltage or watch activity variations.

Divide-by Circuit

The output of the oscillator flows into a system called a clock. This circuit measures the number of pulses that this circuit obtains and releases one pulse when the specified sum is exceeded. A 15-bit counter is used for the 32,768 kHz example. It receives a 15-bit counter generating 1 output pulse for every 32,768 pulses input which emits one pulse per second.

Time Display

A quartz-motion watch can view both analog and digital time. For each pulse the second hand 1/60th of the watch’s circumferences drives an efficient stepper motor for an analog clock. For every pulse of the light a machine monitor adjusts the digits by one.

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