TRF Board
Adjustable transformer

  • TRF board: Adjustable transformer view 1
  • TRF board: Adjustable transformer view 2
  • TRF board: Adjustable transformer view 3
  • TRF board: Adjustable transformer view 4
  • AC voltages up to 260 Vrms

  • DC voltages up to 320 V DC

  • Switchable transmission ratio

  • Measurement of output voltage and current

  • Max. power: 20 W


The transformer board (TRF board) was developed in order to provide voltage to DUTs with a supply voltage of up to 20 W. The input of the transformer board is connected to the output of the PSU board in the test adapter, which is capable of generating a sine wave AC voltage from 0 to 17 Vrms (see PSU data sheet). As the input of the transformer board is connected to the secondary windings of the installed transformer, the PSU voltage is stepped up and voltages of up to 260 Vrms may be generated. Three transmission ratios with various voltage and current ranges are available when the two primary and secondary windings are connected in series or parallel.

The board also offers a DC mode in which the AC voltage is rectified and smoothed by an electrolytic capacitor. A solid-state relay allows the high DC voltage to be connected without causing any wear to the relay contacts.

The output voltage and indicated power are measured, whereby the corresponding signal is connected to the input of the ADX measurement board.


  • AC voltages of up to 260 Vrms
  • Supply of DUTs with supply voltage input
  • Testing protective circuits for surges and undervoltage with variable voltage
  • Generation of country-specific supply voltages from 110 V to 240 V with 50 or 60 Hz


Operating voltage 15 V ± 0.25 V, max. 300 mA
Dimensions160 x 100 mm (total height incl. transformer 40 mm)
Weight0.85 kg
InterfaceRS-422 Guardian protocol
connector X14-pin male connector RM 5mm angled, RIA CONNECT 31176104
connector X264-pin multipole connector DIN 41612
Transformer2 x 115 V / 2 x 12 V, power 30 VA
Voltages ranges65 V AC / 320 mA, 125 V AC / 160 mA, 260 V AC / 80 mA
90 V DC / 320 mA, 180 V DC / 160 mA, 320 V DC / 80 mA
FunctionsBypass (input voltage passes through),
parallel or series switching of primary windings,
parallel or series switching of secondary windings,
switching between AC/DC modes,
switching on/off DC voltage via solid-state relay,
connecting output voltage to measurement board (3:1 division rate),
connecting current sensor to measurement board


Product types

TRF1Adjustable transformer board (1st generation)


We gladly customise our Guardian boards to fulfil your individual needs. Amongst other things, we offer the following services:

We are looking forward to your contact enquiry!