A hybrid car uses two forms energy - petrol or diesel and electricity - for propulsion in an effort to keep CO2 emissions to a minimum and maximise fuel economy.
A regular hybrid (examples are the Toyota Prius+ MPV and Lexus NX SUV) has a conventional petrol or diesel engine which charges a set of batteries that power one or more electric motors.
At lower speeds, say when the car is trundling through town, the electric motors can work alone to drive the wheels, and the internal combustion engine switches off.
But it turns on again if the driver needs a sudden burst of acceleration or the car exceeds a certain speed.
Under these circumstances the electric motor works in tandem with the conventional engine. The electric-only range of these hybrids is limited to only a few miles.
Once the batteries are depleted they need to be charged via the engine and brake regeneration - something the car does automatically.
Plug-in hybrids (examples are the Toyota Prius Plug-In, Hyundai Ioniq and Audi A3 e-tron) have a greater electric range because they have larger batteries and allow the owner to top up the batteries via an electric outlet.
The bigger battery allows them to run on electric power for extended periods, sometimes even at higher speeds, and the brakes are still used for recharging.
Range extenders (an example is the BMW i3 Range Extender and now defunct Chevrolet Ampera) also have a conventional (petrol) engine and batteries with electric motors, but the difference here is that the engine doesn’t power the wheels - it’s only used to charge the batteries, which are also kept topped up via regenerative braking.
Hybrid cars and range extenders are fitted with automatic gearboxes. The tax breaks afforded by their low CO2 emissions mean they’re popular as company cars.