Hewlett Packard 6114A
40 Watt Precision Power Supply, Refurbished

• 0.025% output voltage accuracy
• Pushbutton voltage control
• Five minute warm-up
• May be used with HP-IB Power Supply Programmer
• Overvoltage and overcurrent indicators
• Built-in overvoltage crowbar

HP 6114A 40-watt precision power supply is a high-accuracy instrument designed for use as a low-cost calibrator, a working voltage standard, a system reference supply, or a high-performance lab supply.  It is ideal for applications where accurate, highly stable, and easy-to-use sources of dc voltage is required.

Both models feature automatic dual-range operation.  For example, the 6114A can supply 0-20V at 0-2A, and 20-40V at 0-1A, without manual range switching.  Automatic output current range crossover occurs when the supply is providing greater than one-half of the maximum rated output voltage. 

Pushbutton voltage controls allow the output voltage to be set rapidly and accurately.  The setting is displayed in large, easy-to-read numerals.  A four-digit pushbutton switch increases or decreases the output voltage in unit steps, and the switches go directly from "9" to "0" without backing down.  A fifth digit, set via a separate front-panel control, provides output voltage resolution of 200 µV.

The output voltage accuracy is 0.025% (250 ppm) plus 1 mV - for example, at 40 volts output, the output voltage of 6114A is accurate within ± 11 mV.  This accuracy is attained after only a five minute warm-up, thus making these supplies especially suitable as portable calibrators.

A front-panel current control allows the maximum output current of these supplies to be set to any desired value within the maximum rating.  Using this control, the supplies can be operated as constant-current sources with 0.01% current regulation.  A current mode indicator (a light-emitting diode) immediately lights when the supply is operated in the gross current limit region or when the output current level established by the setting of the front-panel control is reached.  When the indicator is lighted, the output voltage is uncalibrated, but the front panel voltmeter continues to indicate the output voltage with an accuracy of 2%.  A ten-turn current control with a three-digit graduated dial provides 2 mA current resolution.

6114A is designed to be programmed with either the HP Multiprogrammer or the HP-IB Isolated D/A Power Supply Programmer.  Interfacing for Multiprogrammer operation is included as a standard feature in this model; therefore, the addition of Option 040 is not required.  The supply can also be remote programmed by means of an external voltage or resistance.

The output capacitor can be disconnected to reduce current surges, thereby improving the performance of the supply as a constant-current source; this also increases the programming speed by approximately an order of magnitude.  Note, however, that some capacitance at the load may be required to maintain power supply stability under all loading conditions when the output capacitor is disconnected.

A built-in overvoltage protection circuit (an SCR crowbar) monitors the output and reduces the output voltage and current to zero whenever a preset voltage limit (adjustable from the front panel) is exceeded.  This feature provides a convenient method of limiting the maximum output voltage supplied to voltage-sensitive loads.