How to choose the right pH sensor connector?

When it comes to choosing the right pH sensor for your application, it's normally a case of simply working out what operating environment the pH sensor is going to be installed into.

Usually the pH sensor is specified, based on the operating environment, to ensure precision pH readings while maximising longevity of the sensor itself. As there are so many applications where pH sensors are used, we have quite a range of pH sensors incuding some designed for installation into swimming pools; our industrial pH probe range for permanent installation into unpressurised vessels and threaded pH probes for installation into pipes. There are electrodes resistant to Hydrofluoric acid, and we even have a pH electrode specifically designed for clumsy laboratory staff.

Having chosen the preferred pH sensor for your application, we need to ensure that we have the right connection for 'talking' to our pH meter or pH controller and there are a number to choose from.

Stripped & Tinned pH sensor connections

Stripped and Tinned pH connection types are one of the most popular and simple ways to connect a pH electrode to an instrument.
In this image the two connections on the right hand side are the electrode glass and reference connections

The three wires on the far left of the image are for connecting a 3 wire temperature sensor into the Automatic Temperature Compensation input of a pH controller.
BNC pH Sensor Connection

A BNC Connector is probably the most common way of connecting a pH probe to a pH controller.
The plug includes the internal wiring for the pH reference and glass and simply connects to a male BNC plug with no need to worry about which way the wires go around.

The BNC is a particularly popular way of connecting a pH sensor to an instrument because the reciprocal connection includes a sheath which prevents any ingress of liquid, and also assists with the electromagnetic shielding of the pH electrode signal

When ordering a temperature compensated pH probe - the wires carrying the temperature signal will be as per the wires in the stripped and tinned example.
S8 pH Sensor Connector

A design made popular in Europe and in the wet leisure industry.

The S8 plug connector includes two threads, the one at the top of this image is for screwing in an S8 cable. This normally terminates in a stripped and tinned connector for connecting directly to a pH meter.

The second thread at the bottom is a PG13.5 thread and is used to screw the electrode into an holder, normally an inline pH electrode holder.

A reasonably common type of electrode and normally encountered in the wet leisure sector.

For ordering an electrode with an S8 connection, its just the model number - S8, e.g 9069-S8
S7 pH Sensor Connector

The S7 Connector is another European style connector much like the S8 Connector
Where the S7 Connector and the S8 connector differ is that the S7 Connector doesn't include a PG13.5 thread

More commonly found in laboratories than in industrial, leisure or agricultural applications, the S7 is becoming increasingly less common and is often replaced by a suitable electrode with stripped and tinned connections or a BNC connector plug

For ordering an electrode with an S7 connection, its just the model number - S7, e.g 9069-S7
K9 pH Sensor Connector

The K9 Connector is a small pin shaped connector used on older pH instrumentation.
It's quite rare for a customer to request a connector of this type. They were originally found on bench top pH instruments in older laboratories and interesting in some schools

If you do require a K9 connector, then please specify the electrode part number followed by K9, e.g. - 9015-K9.
K8 pH Sensor Connector

Much like the relationship between the S8 connector type and the S7, the K8 connector type includes a threaded end for connecting into a process electrode holder.
Again much like the K9 connector, we rarely come across the K8 connector, but pH electrodes with this connector type can be manufactured if required
Banana Plug pH Sensor Connector

The Banana plug connector is another older design.
Similar to a 5mm telephone switchboard plug, the banana design uses a latch from a spring effect to hold the plug in place.

Again - a much older design but if this is required please get in touch
F-Plug pH Sensor Connector

The F-Plug design was a proprietary connection for connecting a pH sensor to an instrument

While the signal is common, the plug was designed to be tricky to source ensuring that customers had to return to the original instrument manufacturer for an expensive electrode

Thankfully - you can now buy electrodes with unparalleled quality and we can fit a plug that will simply plugging he electrode into the instrument
Miniature Phone Plug pH Sensor Connector

There are a number of telephone style plugs that are viable for connecting a pH electrode to an instrument.
Pictured is the smaller telephone plug connection, but we do offer these in 2.5mm, 3.5mm and 5mm designations.

Again - this is a connection type that is increasingly becoming obsolete but we can certainly source these as required.
Spade Lugs pH Sensor Connector

Spade lugs are a very old design but they were popular because they were simple and they worked.
if you need spade lugs fitting to an electrode this is no problem at all - just use the designation -S and the length of cable in feet, e.g. 9015-10S
US Standard pH Sensor Connector

The US Standard connector plug is as fitted to pH instrumentation from the United States, as the name suggests.
It's not encountered in the UK or Europe all that frequently but as pieces of plant are sometimes imported into the region pH electrodes with this connection type are sometimes required. The designation for ordering a sensor with this type of plug connected is the length of cable in feet and -A e.g. 9015-10A