Picotest J2121A High Power Line Injector - 400V/20A

Product Code: J2121A

Professional High-Power PSRR Testing for Military and Satellite Applications The Picotest J2121A High Power Line Injector represents the pinnacle of power supply rejection ratio (PSRR) testing capability, engineered specifically for high-voltage, high-current applications in military and satellite power systems. This advanced test instrument enables engineers to inject precise modulation signals into DC power lines whilst maintaining electrical isolation and measurement accuracy across a wide frequency spectrum. How PSRR Measurement Works Power Supply Rejection Ratio testing quantifies how effectively a power supply or regulator attenuates unwanted AC signals on its input from appearing at the output. The J2121A modulates the input DC supply voltage using a network analyser source signal, creating controlled disturbances that simulate real-world noise conditions. Engineers measure both input and output signals to calculate the rejection ratio as 20×log(Vinput/Voutput). What Makes Line Injectors Essential: Unlike current probes or injection transformers, line injectors can handle significant DC currents whilst providing galvanic isolation between measurement equipment and high-voltage systems.

Wiring Quick-Start J2121A connection diagram showing VNA, power supply, and DUT connections Basic PSRR Measurement Setup: Power Connections: Connect J2171A power supply to J2121A proprietary power connector Input Power: Connect DC supply positive to red banana jack (+), negative to black banana jack (-) Signal Injection: Connect VNA source output to BNC modulation input DUT Connection: Connect J2121A output banana jacks to device under test input Current Monitoring: Connect current monitor BNC output to VNA channel 1 Voltage Measurement: Connect high-impedance probe to DUT output for VNA channel 2 Connection Point Connector Type Function DC Input +/- 4mm Banana Jacks (Female) 400VDC @ 20A Maximum Modulation Input 50Ω BNC 6dBm Recommended Signal Level Current Monitor BNC 100mV/A Scale Factor Power Input Proprietary (J2171A) 200mA Low-Noise Supply DC-DC Converter Input Impedance Testing Beyond PSRR measurements, the J2121A excels at characterising DC-DC converter input impedance—a critical parameter for avoiding negative resistance instabilities in power distribution networks. The integrated current monitor eliminates the need for external current probes, streamlining the measurement process whilst maintaining accuracy. // Example calculation for input impedance Z_input = V_modulation / I_monitor // Where I_monitor = V_current_out / 100mV/A // Frequency sweep from 100Hz to 1MHz Professional Tip: Always use the included 1Ω calibration fixture to verify measurement accuracy before conducting critical tests. This ensures traceability and validates the complete measurement chain. Comparison with J2120A Line Injector The J2121A addresses applications where the popular J2120A's 50V/5A limits prove insufficient. Key advantages include 8× higher voltage capability, 4× higher current rating, active regulation maintaining constant 750mV voltage drop, and integrated Hall-effect current monitoring that eliminates external probe requirements.