22-01-2018, 08:01 PM
I too have a soft spot for Transformer ratio arm bridges and have a B221, A221, Q221 and Low capacity probes.
The Wayne Kerr ads were in Wireless World August 1969 to May 1970 and are available from the American Radio History site.
I've attached a copy of them all together with a scan of my copy of 'The Transformer Ratio Arm Bridge (Monograph No1) by Raymond Calvert.
Finally the B221 manual available from BAMA site has a good deal about the theory of operation.
I hope this arouses more interest in these relatively under-rated devices.
Jim
The Wayne Kerr ads were in Wireless World August 1969 to May 1970 and are available from the American Radio History site.
I've attached a copy of them all together with a scan of my copy of 'The Transformer Ratio Arm Bridge (Monograph No1) by Raymond Calvert.
Finally the B221 manual available from BAMA site has a good deal about the theory of operation.
I hope this arouses more interest in these relatively under-rated devices.
Jim
