Overview
The Schwarzbeck TK 9261 is an active highimpedance RF-voltage probe equipped with an internal impedance transformer which allows using it with 50 ? measurement devices (such as spectrum and network analyzers or test receivers)
| Specifications | |
| Nominal Frequency Range | 100 kHz - 100 MHz |
| Useable Frequency Range | 50 kHz - 700 MHz |
| Input damping resistance | >100 k? |
| Input capacitance | 1.8 pF typ |
| Output impedance | 50 ? |
| Gain | 0 dB |
| Maximum output level | 1.4 V peak |
| Maximum input d.c. level | 500 V |
| Maximum input a.c. level | 10 Vp-p |
| Output | N-Stecker N-plug |
| According to | RENAULT 36-00-808 |
| Power supply | + 12…15 V 50 mA |
| DC-connector | 5.5 mm / 2.5 mm |
| Ambient temperature | -10° … +60°C |
| Weight | 300 g |
WARNING!
This probe may be used by qualified personnel only. The connection to the DuT must be made before the voltage is applied. The relevant safety standards for working with live-line must be taken into account!
Application
In addition to the EMI measurement with LISNs (which provide a standard impedance, reduce disturbance voltages coming from mains and provide mains voltage to the device under test), voltage probes are used for terminal or line voltage measurement. In this case, a high input resistance and a small capacitance of the probe is required often to prevent putting load to the device under test.
The voltage probe TK 9261 has been designed for high frequency applications, in the range 0.1-100 MHz, and meets the requirements of the RENAULT 36-00-808 automotive standard. Using shorter RF grounding of the probe, measurements up to 700 MHz are possible.
The active part of the TK 9261 is housed in the shielded probe’s head, which is connected to the AC/DC separator with a 1.5 m long coaxial cable. The TK 9261 is powered by the provided power supply. The probe can be also powered by the DC power supply which is often available on the front panel of many measuring instruments, or by using batteries. The maximum current consumption is 50 mA.
The AC/DC separator of TK 9261 is equipped with a Type N male-connector and can be connected directly to the 50 ? input of the measuring instrument.
The measuring point is directly contacted with the measuring tip of the probe. The head of the probe, which is equipped with a 4 mm threaded measuring tip, can be used to connect suitable terminals.
The housing of the probe is equipped with a ground cable which must be connected to ground as close as possible to the measuring point. The ground cable is equipped with a 2 mm plug. Two different lengths are included: 140 mm cable for measurements up to ~100 MHz and 60 mm cable for applications up to ~200 MHz (see Fig. 1 and 2).
A 2 mm crocodile clip is in the scope of delivery.
The TK 9261 probe is protected against overvoltage at the input; however, the maximum input level should not exceed 10 Vp-p. Linear operations are guaranteed up to 1.4 Vp.
The VSWR at the output of the TK 9261 is smaller than 1.5 up to ~200 MHz and reaches a value of 2 at ~400 MHz (see Fig. 3).
Transmission
For function checks of the probe with sine wave signal generators be aware of the output voltage calibration reference with the usual 50 ? load. Either connect a resistor of 50 ? in parallel to the probe (forced match); otherwise almost 6 dB higher reading will be observed.
The housing of the probe is connected to ground directly or with 60 mm / 140 mm cable and 2 mm crocodile clip.
Fig. 1. Transmission (Probe is connected directly to the measurement point)
Fig. 2.Transmission (Probe with screwed 4 mm plug and crocodile clip)
Fig. 3. VSWR at the output (N-plug).
