Automatic External Defibrillators (AEDs) are commonly found in public spaces and within the workplace. The end user is typically tasked with fetching the machine, and then following its instructions without having to think too much about what type of AED it is. However some basic understanding of the different types of machines can ensure the safety of the end user and any bystanders at the scene.

Semi Automatic AED

Semi automatic AEDs require the end user to switch the machine on, place the electrode pads on the casualty’s bare chest and then follow the voice commands. When advised, the end user needs to instruct everyone to stand back and then to press the flashing shock button. 


  • Gives everyone the best possible chance to stand clear when a shock is delivered
  • Limits the risk of electrocution to the end user and bystanders
  • Often more cost effective than fully automated models


  • The user has to remember to press the shock button or nothing will happen
  • It’s an extra step for people to think about when not trained in how to use an AED
Semi automatic AEDs are probably the most popular in the marketplace, whereby the full range can be found here.

Fully Automatic AED

In the same way fully automatic AEDs require the end user to switch the machine on, place the pads in the correct position and follow any voice prompts. However, the key difference with a fully automated model is that the machine does not require the user to press the shock button as the shock is delivered automatically.


  • Shock is delivered automatically without the need for user intervention
  • This eliminates the risk of the user forgetting to press the button


  • There is a risk of electrocution to the user and any bystanders if they fail to stand clear
  • Models are often more expensive than their semi automatic counterparts
If interested in looking at fully automatic AEDs you can find the complete range here.

Training Devices 

The training unit looks exactly like a real life AED and even has the same pads. However the machine is unable to deliver an electric shock and can therefore be placed on manikins or first aid students to help them understand its use. They often have in-built scenarios that will instruct the users to deliver CPR, shock or to check for vital signs.

When you buy an AED, consider asking the company for training with the same model that you have purchased, or you could even buy a training unit that matches your own model that people can practise with. Having some basic knowledge can go a long way when a real life cardiac arrest occurs. 

Tip - It’s not possible to practice with a real life AED, only a training unit.