The Model 4265A is a programmable, bipolar dc voltage source. Output voltage is from 0 to 65.532 vdc in two ranges; 16 and 65 vdc. Programming resolution using the internal reference voltage is 1 mv on the 16 volt range and 4 mv on the 65 volt range. Output accuracy is ±.01% of the programmed level on both voltage ranges. After a 100 /sec settling time, a READY/NOT READY FLAG indicates that the output has settled to ±.01% of the programmed increment for a resistive load. The output current is rated at ±1 ampere maximum and is limited to approximately ±1.1 ampere in the event of an overload or short circuit. The sink current (milliamps) is rated at 1000-10 Eout maximum. A Programmable Current Limiter (Option -06) is available to allow programming the maximum output current to a lower level. A current limit flag indicates when a sink or source current overload exists with or without the -06 Option. 1-3. Programming requirements are compatible with DTL or TTL logic levels. Contact or relay closures can also be used. The voltage source is programmed on the low range using straight binary coding. The high range is also programmed in the same manner, but the actual output is four times the programmed level. Two's complement coding is required for negative outputs when the Isolated Control Logic (—01 Option) is installed. All programming inputs and flag outputs are available through a 50 pin Amphenol, Blue Ribbon connector located on the rear panel. A +5 vdc output is also available at this connector and is used to provide power for external programming circuitry. Negative logic is employed for programming. The logic levelsi are as follows: Logic “0” = +2.0 vdc to +5.0 vdc or open circuit Logic “1” = 0 to +0.4 vdc or short circuit to LOGIC GRD. 1-4, Three options are available to provide tailoring of the power supply to fit application requirements. These options are identified by numeric designations -03, -06, and -09. A description of each option is provided in Table 1-1. These options may be installed at the factory when the instrument is ordered or in the field at a later time. 1-5. Physically, the power source is completely solid state. Plug in printed circuit boards, with easy to reach test points and adjustments, are used for ease in servicing. The unit is forced air cooled. This results in lower component temperatures and thus higher reliability than would normally be obtained in a source of this power capability. The chassis is designed for bench top use, or it can be installed in a standard equipment rack by using the Accessory Rack Mounting Fixtures.