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History of the manufacturer  

AVO Ltd.; London

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Name: AVO Ltd.; London    (GB)  
Abbreviation: avo
Products: Model types

The company was started in 1923, and was known as the 'Automatic Coil Winder and Electrical Equipment Co.' located at Douglas Street, London SW1”

Later they renamed to 'AVO Ltd.' (which should not be mixed up with 'Avo International Ltd.')

AVO is well known for it's very solid and reliable measuring instruments, and - coil winding machines.

Avometer is a British trademark for a line of multimeters and electrical measuring instruments,
The brand is now owned by the Megger Group Limited.

The invention of the first multimeter in 1923 is attributed to Scottish British Post Office engineer, Donald MacAdie.

The Automatic Coil Winder and Electrical Equipment Company (ACWEECO), founded in 1923, was set up to manufacture the Avometer and a coil winding machine also designed and patented by MacAdie.

Support for AVO coil winders now by 'Cranleigh Coil Winding Equipment Ltd.', The Common, Cranleigh, Surrey UK, Tel. 01483 273536 

Founded: 1923
Closed: 1989

Donald MacAdie, a Post Office engineer, dissatisfied with having to carry many separate instruments, invented a meter that could measure Amps, Volts and Ohms - the multifunction meter was named AVO. MacAdie took his idea to the Automatic Coil Winder and Electrical Equipment Co.
The first AVO was put on sale in 1923, initially a DC-only instrument.  Although a shareholder of ACWEECO, Mr MacAdie continued to work for the Post Office until his retirement in 1933. His son, Hugh S. MacAdie, joined ACWEECO in 1927 and became Technical Director.

1939 Additional premises at AVOCET House 92 96 Vauxhall Bridge Road

1957 Name changed to AVO LTD.

1957 Became public company: Avo Ltd, of Avocet House, Vauxhall Bridge Rd, London, to manufacture instruments with the AVO trademark.

1958 Metal Industries Ltd acquired Avo Ltd, including its subsidiary Taylor Electrical Instruments Ltd.

1966 Moved to new premises in Archcliffe Road in Dover.

1967 Metal Industries Group, MIG was bought by the Thorn Electrical Industries group who quickly became part of EMI

1970’s Various companies were bought and moved to the Dover site including:

  • Foster Transformers
  • Evershed
  • Megger Instruments

1987 Renamed Megger Instruments Ltd

1991, due to the popularity of the AVO products the company changed the name to AVO Megger Instruments Limited.

2000 the company became known as AVO International Holdings Limited.

2002 as AVO International Limited.

Finally the whole Megger group changed its name to Megger Group Limited in 2002, as it is known today.

[Wikipedia 2017]

Some models:
Country Year Name 1st Tube Notes
GB  75 Digital Avometer DA112 XN12  AVO Digital Avometer, 10 MΩ / V transistorized multimeter, 3-½ digits 26 transistors an... 
GB  40 AVO Exposure Meter Model 1   Later version of the AVO photoelectric exposurer meter. 
GB  47–50 Valve Characteristic Meter MK 1   First model of the AVO Valve Characteristic Meter, very different from the 2-panel valve t... 
GB  36 Universal AvoMeter (AVO Meter) 7 Mk.i (1) [Early]   Seventh version of the Avometer, 46 ranges. The first version to incorporate auto cut out.... 
GB  34 AvoMeter (AVO Meter) 6 [DC Only]   Sixth version of the Avometer, DC only with 22 ranges with external battery adjust ad... 
GB  32 Universal AvoMeter (AVO Meter) 3   Third version of the Avometer, 20 ranges with the AC capability added. Bakelite front p... 
GB  58 Universal Measuring Bridge Type 1 12AU7  DC is used to measure resistance and AC (1000Hz), for capacitance and inductance. Resis... 
GB  33 DC AvoMinor (AVO Minor Meter) 1933 Version   DC Volt-Ohm Meter First of the DC Avominor series of small multimeters. This version... 
GB  35 AVO Exposure Meter   Photoelectric light meter for photography Calibration: Film speed: 200 - 5000 H&D. ... 
GB  34 Universal AvoMeter (AVO Meter) 5   Fifth version of the Avometer, 36 ranges. Bakelite front panel with an aluminiunm case.... 
GB  33 Universal AvoMeter (AVO Meter) 4   Fourth version of the Avometer, 34 ranges with the "Divide by 2" button added. This dou... 
GB  27 AvoMeter (AVO Meter) 2   Second version of the Avometer, 13 ranges, DC only. Bakelite front panel with an alumin...