sensing is especially useful for CV operation with load impedances that vary or have significant lead resistance. It has no effect during CC operation. Because sensing is independent of other power supply functions, remote sensing can be used regardless of how the power supply is programmed. Note that with remote sensing, voltage readback monitors the load voltage at the sense points.

Figure 4-5. Remote Voltage Sensing

Figure 4-6. Allowable Load Lead Voltage Drop with Remote Sensing

The maximum voltage available at the power supply output terminals during remote sensing (see Figure 4-6) is the maximum voltage (20.2 V or 50.5 V) rating, plus one volt (i.e. 21.2 V or 51.5 V as shown in Figure 4-2).This allows a voltage drop of 0.5 V per load lead, or one volt total. For lower output voltages refer to Figure 4-2.

Remote Sense Connections

Remember to turn off the power supply before making or changing any connections on the rear panel terminal blocks. Connect the unit for remote sensing by first disconnecting the straps between sense and load terminals. Then make your connections as shown in Figure 4-5. Connect the sense leads as close to the load as possible. See pages 47 & 48 for information on selection of load lead wire gauge. Best results will be obtained by using the shortest load leads practical. It is recommended that you keep your load leads under 14.7 meters (50 feet) per lead because of inductance effects.

The sense leads carry only a few milliamperes of current and therefore, can be lighter gauge than the load leads. However, note that any voltage drop in the sense leads can degrade the voltage regulation of the supply. Try to keep the sense lead resistance less than about 0.5Ω per lead (this requires 20 AWG or heavier for a 50 foot length). You can use the following formulas to calculate the CV load regulation error when using remote sensing:

50 Output Connections and Operating Information

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HP 6621A, 6623A, 6624A manual Remote Voltage Sensing, Remote Sense Connections
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6624A, 6621A, 6623A specifications

The HP 6623A, 6621A, and 6624A are precision DC power supplies widely recognized for their reliability and performance in various laboratory and industrial applications. These models are part of HP's 662X series, designed to cater to the needs of engineers, researchers, and technicians who require accurate power sources for their testing and development activities.

The main features of the HP 6623A, 6621A, and 6624A include their high stability, low ripple, and excellent load regulation, ensuring that the output voltage and current remain stable during testing. The power supplies provide multiple output channels, allowing users to power multiple devices simultaneously. The flexibility in setting voltage and current levels makes these models ideal for a wide range of applications, including semiconductor testing, device characterization, and system integration.

One of the standout technologies in the HP 662X series is the use of smart design techniques that minimize noise and enhance output performance. These power supplies incorporate advanced feedback mechanisms to maintain steady output, even under varying load conditions. Additionally, they feature programmable outputs, which means users can adjust the output levels through a connected computer or control system, streamlining the testing process and improving efficiency.

The HP 6623A model offers three independent outputs, with total power capabilities of 40 watts. It includes a 0-20V output, which can deliver up to 2A of current, along with two additional outputs that are adjustable. The 6621A provides a single output option, delivering a maximum of 20V and 2A, making it well-suited for simple applications where a single power source is required. In contrast, the HP 6624A stands out with its four independent output channels, providing a total of 60 watts, making it the most versatile of the three models.

Characteristics of these power supplies include user-friendly interfaces, allowing for easy configuration and monitoring of settings. LED indicators provide real-time feedback on voltage and current levels, enabling users to quickly assess the performance of their tests. Moreover, built-in protection features safeguard both the power supply and the connected devices from overvoltage and overcurrent conditions.

Overall, the HP 6623A, 6621A, and 6624A power supplies embody advanced engineering and design, making them invaluable tools for professionals looking for high-quality, reliable power sources for their electronic testing needs.
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