The Model 204C is a stable signal source that produces sine wave frequencies between 5 Hz and 1. 2 MHz in six ranges. The output level is variable from 0 to 5 volts rms from a constant 600 ohm source. When working into a 600 ohm load, the maximum output level is 2. 5 volts rms. 1-7. A SYNC feature is included in the Model 204C. The SYNC jack on the front panel provides an output sync voltage of 1. 7 V rms, or accepts an external signal to synchronize the oscillator. This feature permits several oscillators to be synchronized to the same frequency or harmonics thereof. 1-8. The output of the Model 204C may be isolated from the cabinet. This floating output is balanced to better than 40 dB below 200 kHz with an isolated, battery operated instrument, or better than 40 dB below 20 kHz with an instrument having an ac line connection. 1-9. The standard Model 204C contains an ac power supply that can be operated from 115/230 volts ac, 50 to 400 Hz. The instrument is also available with a mercury battery power supply as an Option 01, or with a rechargeable nickel cadmium battery power supply as an Option 02. The various power supplies can easily be interchanged by removing the instrument covers, unplugging one supply and plugging another in its place.