RA Mayes | Solar Electronics | Current and Injection Probes

Manufactured and Serviced in North Hollywood CA

CURRENT PROBES

Current probes required by various EMI specifications (such as MIL-STD-461/2) are toroidal transformers designed to measure RF currents on active power lines or other conductors.

APPLICATION

A current probe is used as a “pick-up” device for measuring RF current in single conductors or cable bundles when connected to the 50 ohm input
of a radio frequency interference measuring receiver or spectrum analyzer.

DESCRIPTION

Direct connection to the conductor carrying EMI current is not necessary, since the probe may be opened for insertion of the conductor into the window of the toroid and then closed again to form a toroidal transformer with the conductor acting as a one-turn primary.

A correction factor graph is provided to convert measured microvolts to EMI microamperes. When the EMI current is measured in dB above one microvolt as indicated on a conventional EMI meter, the correction factor will convert the measurement to dB above one microampere.

The correction factor is the inverse of the transfer impedance, Zt. Each probe is shipped with a graph of the correction factor versus frequency, keyed to the serial number on the probe. Under certain conditions, a current probe can be used to inject low level RF signals into individual wires or cable bundles.

INJECTION PROBES

Specifications require the injection of large high frequency currents into cable bundles and individual wires, using inserted secondary toroidal transformers placed around the conductors being tested.

APPLICATION

High power RF amplifiers with 50 ohm output impedance are used to deliver voltage to the injection probe. The wire or cable through the window of the probe acts as a secondary of the toroidal transformers. This test method is intended to be used instead of earlier methods, such as CS-01, CS-02, and RS-02 of MIL-STD-461.

DESCRIPTION

Bulk Current Injection Probes are available in two styles:

1. Fixed window style where the wire(s) under test must be passed through the window.

2. A split toroidal design where the probe can be opened up and clamped over the wire(s) under test.

Each probe is calibrated for insertion loss and transfer impedance in a test fixture designed for the particular window size. This fixture provides a signal path with a low Voltage Standing Wave Ratio. A typical fixture is Solar Type 9125-1, used for probes with 32 to 44 mm diameter windows. Ask for details on this and other test fixtures.

RFI/EMI Current and Injection Probes

CLAMP-ON INJECTION PROBES
SOLAR TYPE NO.	WINDOW DIAMETER	WINDING CURRENT	RATED WATTS	INSERTION LOSS				FREQUENCY RANGE
SOLAR TYPE NO.	WINDOW DIAMETER	WINDING CURRENT	RATED WATTS	UNDER 6 dB	UNDER 10 dB	UNDER 15 dB	UNDER 20 dB	FREQUENCY RANGE
9108-1N	1.25" (32 mm)	10	50			120 KHz - 70 MHz	60 KHz - 150 MHz	10 KHz - 200 MHz
9120-1N	1.25" (32 mm)	30	50		12 MHz - 600 MHz	7 MHz - 900 MHz	4 MHz - 1GHz	4 MHz - 1 GHz
9121-1N	1.25" (32 mm)	30	50		100 MHz - 550 MHz	50 MHz - 800 MHz	30 MHz - 1GHz	10 MHz - 1 GHz
9142-1N	1.50" (38 mm)	50	200	10 MHz - 350 MHz	5 MHz - 430 MHz	2.5 MHz - 500 MHz	1.5 MHz - 500 MHz	2 MHz - 500 MHz
9144-1N	1.50" (38 mm)	26	100		200 KHz - 8 MHz	70 KHz - 90 MHz	40 KHz - 100 MHz	10 KHz - 100 MHz
9217-1N	1.50" (38 mm)	26	100	800 KHz - 1.5 MHz	500 KHz - 40 MHz	250 KHz - 100 MHz	150 KHz - 100 MHz	10 KHz - 100 MHz
9310-1N	2.62" (67 mm)	26	100		15 MHz - 450 MHz	800 MHz - 650 MHz	4 MHz - 800 MHz	5 MHz - 800 MHz
9607-1N	1.25" (32 mm)	10	50		500 KHz - 1 MHz	200 KHz - 30 MHz	120 KHz - 300 MHz	10 KHz - 300 MHz
Injection probes can also be used as current probes. A correction factor graph and instructions for its use are supplied.

CALIBRATION FIXTURES
Note: Except for p/n 9125-1 and 9357-1 The probes are supported and centered in the fixture
Model	Description
9125-1	For Injection Probes, 1.5" (32 mm - 44 mm) diameter window. 20 Hz to 500 MHz. Type BNC connectors.
9125-2	For Solar 9119-1N Probe and similar, 1.25" (32 mm) diameter window. 400 MHz to 3 GHz. Type N connectors.
9251-1	For Eaton, Stoddart and Solar Probes, 1.25" (32 mm) diameter window. 20 Hz to 500 MHz. Type BNC connectors.
9254-1	For Eaton, Stoddart and Solar Probes, 2.62" (66 mm) diameter window. 20 Hz to 500 MHz. Type N connectors.
9321-1	For Eaton, Stoddart and Solar Probes, 0.75" (19 mm) diameter window, totally enclosed. 20 Hz to 1.5 GHz. Type BNC connectors.
9330-1N	For Eaton, Stoddart and Solar Probes, 1.25" (32 mm) diameter window, totally enclosed. 20 Hz = 1.0 GHz. Type N connectors.
9357-1	Clam Shell Fixture for Solar 9335-2 Probe. 20 Hz to 100 MHz. Type BNC connectors.