PH pH ph pH = power of Hydrogen pH meter is electric device used to measure : hydrogen-ion activity (acidity or alkalinity) in solution.

at pH 7 (neutral pH) the electrode produces 0 volts. Acids produce positive voltages Bases produce negative voltages. a standard pH electrode generates a voltage of about 59 mV per pH

pH meter consists of : Glass electrode Reference electrode Amplifier Voltmeter Temperature controller

History of the pH Meter The first commercial pH testers were built around 1936 by Arnold Beckman in the United States and by Radiometer in Denmark. Glass pH electrodes that have a potential dependent on activity of H+ ions were constructed already 1906. The main problems to construct a pH tester was to design a sensitive high-gain amplifier and pack it in a compact, portable unit. Since then pH testers became one of the most popular and important instruments used by chemists and non-chemists in labs, field and industrial environment. The basic ideas behind the pH tester haven't changed. The reliability and precision of today's pH tester are of course much better. Also many of the modern pH instruments are digitized and able to communicate with computer.

Types There are three different types of pH meters: Portable , bench and Fixed type. • Portable to perform measurements outside the laboratory. • Bench They are typically used in a laboratory tester is usually more precise and has more options. • Fixed pH meter or Continuous inline pH meter used to continuously monitor the pH in drinking water treatment plants for process control are designed to with stand harsh environments.

Fixed pH meter Continuous inline pH meter used to continuously monitor the pH in drinking water treatment plants