Preamplifier For Transistorized Frequency Inverter

The Preamplifier FR-FA is mainly used to convert and amplify output signal from a speed setter to make the output signal applicable as frequency setting signal to the FREQROL inverter.
In general, the output signal from the speed setter is adjustable within a ratio of 1 to 5, that is, within a range from 2mA to 10mA, or 4mA to 20mA, for example, thus permitting frequency only within the ratio of 1 to 5.
When the Preamplifier is used, the output from the speed setter may be easily changed within a range of 0% to 100%.
The Preamplifier is provided with an input terminal to serve as an OP amplifier (operational amplifier). Also, since the unit has a built-in output clamp circuit, it can also be utilized as an OP amplifier with output clamp.