Details

Six different sources of power supply are available, which work indepently one from another and are supplied from the network. Thus are plate. direct-current. voltage, -plate. alternating-current voltage, control grid voltage; screen“grid voltage, filament voltages and the source of power supply for a leakage indicator pane

Three moving coil-instruments are installed with many ranges of which some are switchable on different functions. A tester for anode current (IA. . . . ) a moving coil-instrument with 4000 Ω/V sensibility for grid voltage and grid current as well as for negative and positive tensions (UG1 and IG1 measurements) A tester with 4000 Ω/V sensibility for measuring of anode tension (UA-measurement) screen grid voltage (UG 2 measurement) and screen grid current (IG2 measurement).

High loaded control device. The potentiometer in order to adjust the anode voltage is a 75 W potentiometer for 200 mA permanent charge. The control device for the screen grid voltage is a 20 W potentiometer for 40 mA permanent charge.

Main switch the same as in model W 19 which takes care of all examinations and measurements in a forced line, first of all the tube. for mechanical mistakes (electrode short circuits, surface leakage currents etc. etc. Then he puts the source of currents on the tube for measuring.

Plate direct current voltages (UA... V=) will be produced by a Silicon rectifier CSK B 500 C1200 which works in a full wave rectification and possesses different ranges. The ranges 0 ... 25 V=, 0 ... 10 V=, 0... 50 Ve, 0 ... 250 V= and 0 ...500 V= can switched on. When using one of these ranges, the tube tester belonging to it will be switched on the same range, avoiding any errors. In the ranges until 250 V=, 150 mA current can be taken, in the range of 500 V= current of 100 mA can be taken.

Plate current (IA... mA) can be measured in different ranges. Available are the ranges 0 . . . 250 µA (5 µA can be readed) 0...1mA, ...2,5 mA, ... 5 mA ... 10 mA, ... 25 mA, ... 50 mA, ... 100 mA, ... 250 mA.

Plate alternating current (UA ... V~) the way you use them for measuring rectifying valves, took to the constant of instruments: of 10 V~, 30 V~, 60 V~ and 100 V~, When working with test cards it will be switched on correctly.

Control grid voltages (UG1 ... V=) are available positivly and negativly, i. e. in the ranges 0 ... 5 V=, 0 ... 25 V= and 0 ... 100 V=. If one of these ranges has been selected, then automatically the instrument works in the same range, therefore a very simple service. The grid source of current supplies through a filter chain a well smoothed current.

Control grid currents (IG1 ... µA) can be measured. The following ranges are available: 0 ... 250µA (5 µA can still be read), 0 ... 1mA, ... 2,5mA, ... 10mA, 0 ... 25 mA.

Screen grid voltages (UG 2... V=) exist with the ranges 0...10V=, ...50V=, ... 250 V=.

Screen grid currents (IG2...mA) can be tested in the ranges 0... 250 µA with 5 µA as the smallest one to be read, 0...1mA, 2,5mA, ... 10mA, ... 25mA

Filament voltages (Uf... V~) are available as in model 19 as constant of instruments, i. e. 48 different constants of instruments from 0,7 V . 117 V. It is possible to check them by switching on a tester.

Filament current (If ... A) can be tested additionally by switching on of a tester on two available jacks.

All kinds of valve sockets are installed in the same way as in our model W 19. In order to install more valves, room enough is available.

Subminiature valves can be tested, never mind whether they fit into the sockets, of 8 polar round, 5 polar, 6 polar or 7 polar straight or whether these valves have no sockets at all or if they possess wire connections. In order connect valves without sockets, cables are supplied with and the existing test cards render it possible to have an easy service. Also other valves without a socket as for example EY 51, 9 X 2 etc. etc. can be tested with these special cables (German Patent).

Also the Germaniumdiodes can be tested. These will be connected with special cables and will be testedin two jacks, marked as diode circuit symbol. Nearly all these diodes can be tested only with 1,00 V in the forwarded direction, using 3 V they are already distroyed. In order to avoid it, it is useful to test only the power equipment part and the current will break down. In other ranges it will be different and the diodes can be tested more higher.

Red warning light on the front side of the instrument lights up as long as the instrument is under current.

More than 1100 test cards for nearly 10000 valves and test cards for Germaniumdiodes belong to each of W 20. These test-cards make the service easier, contain all technical datas of the valve, as f. e. service data etc. etc.

With a tube tabular book in a clamping folder. It contains in a numerical and alphabetical sequence; all valves which can be tested with the test-Gards, that is to say 10000 types with indications for the number of test cards, manufacturer and the type of reserve ordnance. The book possesses a clamping cover, the pages can be exchanged. It contains also the instruction book for W 20 with switch sketches. Also any questions which may arise are contained in the mentioned book thanks to our experience in the last 25 years.

Also a quick test for valves thanks to a simple service is possible as well as you find it for our W19 when working with test cards. You only need to adjust what you find on the test card as „test-operation“ At least and at last they are three tensions, i. e. plate voltage, grid voltage and screen grid voltage. The rest of it as base connection, filament voltage etc. etc. will be done by the test card automatically and the valve range „Good“ etc. of the test card are valid.

Summary: The Tube-Tester W 20 is for the technician in order to test with test cards a quick test for valves and also tests in a simple way, but also large tests can be made for characteristic lines, mutual conductance and other valve-datas. Thanks to the high voltage of 500 V and the high possible consumption of current also larger valves can be tested with the W 20. But also Germaniumdiodes and subminiaturvalves can be tested and in the near future it will be possible to test also other things.