When it comes to garnering attention, few signs do it better than an illuminated LED sign. But sometimes, like when a bank drive-thru is closed, a sign should not be lit as it could mislead the reader. This is why LED signs need the ability to be turned off and on at the user’s discretion. A power toggle switch is the most straightforward method to control an LED sign. However, not every sign requires the same type of switch. This article will define key terms related to switches and explain various kinds of switches to better help you choose the best controller for your LED sign.
Understanding Some Key Terms
Before diving into switch types, it’s important to understand some of the terms used to describe them. Let’s dive right in.
Switch - a device for making and breaking the connection in an electric circuit. It responds to force and off.
Pole - the number of circuits that a single switch can control for one operation of the switch.
Throw - the number of possible output connections that can be made using the switch.
Gang – switches on an electric box’s wall plate. Signal-Tech offers up to a 9-gang switch.
With some common terminology defined, let’s move forward to typical switch types.
Single Pole Single Throw (SPST) Switch – Two Positions, On/Off
An SPST switch is very simple as it only has a single input and can only connect to one output. Further, it only has one input terminal and one output terminal. SPST switches essentially serve circuits as on-off switches; when the switch closes, the circuit is on; when the switch is open, the circuit is off. An SPST power toggle switch is an on-off switch for all intents and purposes. Its best application is for single-message LED signage, such as an "in-use" sign, illuminated when on, not illuminated when off.
Single Pole Double Throw (SPDT) Switch – Three Positions, On/Off/On
An SPDT switch only has a single input and can connect to and switch between the two outputs. This means it has one input terminal and two output terminals. This type of switch can serve several functions depending on the wired circuit. For instance, it can act as an on-off switch or connect circuits to any two paths where a circuit may need to function. This type of switch best applies to direct-view, two-message LED signs, such as open-closed, to ensure the sign is illuminated “Open,” illuminated “Closed,” or off.
Double Pole Double Throw (DPDT) Switch – Two Positions, On/Off/On
A DPDT switch is just two SPDT switches. It has two inputs and four outputs; each input has two corresponding outputs to which it can connect, and all four outputs are separate. It is best used for controlling three-message LED signs when one message is to be illuminated (on) when either of the other two messages is also on. A practical application for this switch for LED signs is an Open | Closed sign for ATMs. The sign’s “ATM” message can be illuminated with the “Open” message, illuminated with the “Closed” message, or turned off completely.
Finally, a Double Pole Single Throw (DPST) switch is used to control two different signs of different voltages from a single switch. However, these power toggle switches are not typically used for controlling LED signs as signs in one gang normally follow the same voltage.
Choosing the right power toggle switch for your LED sign is an important, but often overlooked, aspect of implementing LED signage. Having the right switch ensures signs function correctly, their message is seen when required, and your business gives the best possible customer experience. Signal-Tech’s switches are constructed of stainless steel for durability and longevity, pre-wired, and ready to install upon delivery. Ready to purchase a switch? Check out our entire lineup of power toggle switches here, and contact us anytime for additional assistance.
