# Cal Test CT3688A Active Differential Probe Kit, 200 MHz, 10x ±20V # Cal Test CT3688A Active Differential Probe Kit, 200 MHz, 10x ±20V ## Key Features At A Glance - 200 MHz bandwidth (-3 dB) with 1.75 ns rise time - 10x attenuation ratio with ±1% accuracy - Up to ±20 V maximum differential input (DC + AC peak) - ±60 V maximum common mode input (DC + AC peak) - CMRR (typical): -80 dB @ 100 Hz, -50 dB @ 10 MHz - Meets IEC 61010-031 safety standard - Powered by included 9 V battery or USB cable - Compatible with oscilloscopes from all major manufacturers The CT3688A is an active differential probe kit from Cal Test Electronics, providing 200 MHz bandwidth with a 10x attenuation ratio for small-signal differential measurements up to ±20 V (DC + AC peak). It can also handle up to ±60 V (DC + AC peak) of common mode input. The probe can be battery operated using the included 9 V battery or powered directly from an oscilloscope using the included USB power cable, and it connects to a standard 50 Ω oscilloscope input. Differential probes allow safe, accurate measurement between two voltage points where neither point is referenced to ground. This makes a differential probe the appropriate tool whenever the signal of interest is floating relative to chassis ground and a single-ended probe would either short the measurement or be unsafe. The CT3688A is compatible with oscilloscopes from all major manufacturers, so it can be added to an existing bench setup without changing the host instrument. ValueTronics stocks and holds its own inventory in a 20,000 sq ft secure warehouse at 1675 Cambridge Drive in Elgin, Illinois. That combination lets engineers source the right probe in the right condition with confidence in how it was handled. ## Accessories Supplied - Differential probe - (2) Sprung hook probes, 1000 V, CAT III, 20 A (black & red) - (2) Alligator clips, 300 V, CAT II (black & red) - 9 V Battery - USB Power Cable - Foam-lined plastic case ## Product Core & Specifications Specification Value Electrical Specifications Bandwidth (-3dB) 200 MHz Rise Time (10%-90%) 1.75 ns Attenuation Ratio 10x Accuracy ±1% CMRR (typical) \-80 dB @ 100 Hz \-50 dB @ 10 MHz Maximum Differential Input Voltage (DC + AC peak) ±20 V Maximum Common Mode Input Voltage (DC + AC peak) ±60 V Absolute Maximum Rated Input Voltage (each side to ground) 40 Vrms CAT I Input Impedance 500 kΩ // 7 pF (each side to ground) Output Voltage Swing ±2 V (driving 50 Ω oscilloscope input) Offset (typical) ±2 mV Noise (typical) 0.3 mVrms Source Impedance 50 Ω Power Supply CT4122 USB Power Cable (included) or 9 V battery (included) Mechanical Specifications Weight 200 g Dimensions (L x W x H) 111 mm x 22 mm x 14 mm BNC Cable Length 120 cm Input Leads Length 50 cm Environmental Specifications Operating Temp/Humidity \-10°C to 40°C / Up to 85% RH Storage Temp/Humidity \-30°C to 70°C / Up to 85% RH Pollution Degree Pollution Degree 2 Altitude Operating: 3,000 m Non-operating: 15,300 m > **Important:** Maximum differential input: ±20 V (DC + AC peak). Maximum common mode input: ±60 V (DC + AC peak). Absolute maximum rated input: 40 Vrms CAT I (each side to ground). > **Important:** Meets IEC 61010-031 safety standard. > Recommended pairing: the CT3723 9 V DC Power Adapter, listed in the order information, provides an alternative to the included 9 V battery or USB power cable. ## About this New unit This is a brand-new, factory-sealed unit, supplied exactly as it arrives from the manufacturer and backed by the full manufacturer warranty. For the exact configuration, available options, included accessories, or current lead time for your application, our Test Architects can confirm the details before you order. ValueTronics supplies both new and used test and measurement equipment. New units ship factory-sealed, exactly as received from the manufacturer; every used unit is inspected and functionally verified in-house at our 20,000 sq ft secure facility in Elgin, Illinois before it ships. Our Test Architects can help you select the condition, calibration, and configuration that fit your application. **Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.** ## Details - **Price:** 1188.05 USD - **Vendor:** Cal Test Electronics - **Type:** Diff Probe - **Tags:** Accessories, Cal Test Electronics, Differential, Manufacturers, Other Equipment, Probe, product_manual_group_2, Product_new ## Variants | Variant | Price | Available | |---------|-------|-----------| | Default Title | 1188.05 USD | In stock | ## Images - Cal Test CT3688A Active Differential Probe Kit, 200 MHz, 10x ±20V --- > Source: [ValueTronics](https://valuetronics.com/products/ct3688a-cal-test-differential-probe-new) > Updated: 2026-06-20