Factory installed Delta TCA RF single scale Ammeter System option for the CPB-1A. The complete series of 5, 10, 20, 40, 80 and 160 Ampere single scale RF Ammeters with appropriate sampling transformer are available. With the RF Ammeter mounted on the bridge panel, the total RF power is easily determined from the load current and measured resistance.The Transformer Coupled Ammeter (TCA) series of RF Ammeters provides AM broadcasters with an accurate and reliable instrument for measuring common point and antenna base currents. The ammeter uses a toroidal current transformer to obtain a sample voltage proportional to the RF current flowing in a conductor. This voltage sample is connected by a 50-ohm coaxial cable to a temperature compensated rectifier circuit. This circuit converts the RF voltage to a DC voltage that is applied to a linear scale meter, calibrated in RF Amperes, for display of current magnitude. The ammeter provides a DC output voltage to drive a remote indication instrument that may be calibrated against the primary meter and used for remote indication. Ammeters that include relays to remotely control the operation of the meter are also available.