Tektronix 570 Vacuum-Tube Characteristic-Curve Tracer (1968)

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BAMA 570 Free Manual and Schematic Download Site

Orig CostLow BidHigh Bidaverage
$1100 (1968) ...
no buy ($3351.27 < reserve) 12/29/02 #3101710358 pearl.hifi (15 bids)
no buy ($1025 < reserve) 1/5/03 #3103940580 pearl.hifi (8 bids)

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    Type 570 Vacuum-Tube Characteristic-Curve Tracer. This rare instrument is the 575's counterpart for testing vacuum tubes. The unit was provided with a set of various tube sockets which can be installed and jumpered to the appropriate test points. Tubes can be checked for gain and matched if desired. Contributed by Bruce Rogers


    Some Specifications and Features of the Tektronix 570 Characteristic-Curve Tracer
    Vertical Deflection:
    200uA to 50mA per div, 11 steps in a 1,2,5 sequence, with an additional range of 100mA/div being toggle switch selectable while in the 50mA/div setting.
    Display of one of: plate, screen or control grid current is switch selectable.

    Horizontal Deflection :
    100mV to 50V per div, 9 steps in a 1,2,5 sequence.
    Display either: plate or control grid voltage is switch selectable.

    Plate Sweep :
    continuously variable from 0 to: 6.5, 13, 26, 65, 130, 260, 390, 650V full wave AC @ 120Hz. and a max. current of 250mA avg. and 1A peak.

    Grid Step Generator :
    The number of steps per family is selectable from 4 to 12 with grid voltage steps in a range from 100mV to 10V per step with 3% accuracy.
    The maximum current is 50mA avg. and 100mA peak.
    This generator's output may be offset in the positive direction by as many as 8 steps (+80V) thereby allowing the investigation of operation in the "grid current" region as long as the supply's current limitations are respected.

    Positive DC Voltage :
    This regulated supply provides five calibrated steps from 0 to: 20, 50, 100, 200, 300VDC @ 3% accuracy.
    Continuously variable, uncalibrated, from 10 to 300V.
    Maximum current of 50mA avg. and 150mA peak.

    Negative DC Voltage :
    This regulated supply provides a continuously variable output through the range of 0 to -100VDC and is used to set bias voltages i.e. to vary the voltage on suppresser grids in pentodes where the G3 connection is brought to a separate pin.
    The Type 570 Characteristic-Curve Tracer presents a graphic analysis of vacuum-tube characteristics under a wide range of operating conditions.

    Calibrated horizontal and vertical deflection make it possible to measure the characteristics directly or the curves may be compared with preselected tube characteristics that have been reproduced on a mask over the cathode-ray tube.

    Front panel switching between two test sockets permits rapid comparisons between two tubes or between two sections of the same tube.

    By means of various switch settings for the vertical and horizontal deflections the following displays are possible:
  • Plate current vs. plate voltage
  • Screen current vs. plate voltage
  • Grid current vs. plate voltage

  • Plate current vs. control grid voltage
  • Screen current vs. control grid voltage
  • Grid current vs. control grid voltage

    The 570 can configured to provide displays of the characteristics of tubes connected in cascode, active plate load, compound connection such as the triode/tetrode operation of two output tubes or -- with an easily built additional sweep supply in series between the output of the +DC supply and the screen of a beam tetrode or pentode -- the characteristics of a tube with variable "percentages" of ultra-linear operation.

    Additionally, the 570 can display the characteristics of solid state devices such as zener diodes, N-channel small-signal depletion-mode JFETS used in differential stages and high voltage, high power, enhancement mode MOSFETS.