Heathkit Model IG-4505

Oscilloscope Calibrator

Calibration Procedure

· Turn on the oscilloscope and allow it to warm up and stabilize.

· Disconnect all external components from the front panel terminals.

Ancillary Equipment Needed

Analog Voltmeter

Digital Voltmeter

Oscilloscope

* * * * * * *

INITIAL SETUP

(    )         Set the POWER switch SW101 to the OFF position.

(    )         Set the VOLTS OUT switch SW2 to the 1V position.

(    )         Set the MULTIPLIER slide switch SW102 to the X1 position.

(    )         Set the CAL control R4 [on the circuit board] to the center of rotation.

* * * * * * *

OSCILLOSCOPE SETUP

(    )         Set the VERTICAL INPUT attenuator to the 0.5V/cm position.

(    )         Set the HORIZONTAL SWEEP RATE to the 1 msec/cm position.

(    )         Connect the BNC connector from the Oscilloscope Calibrator to the vertical input of the oscilloscope.

* * * * * * *

INITIAL TESTS

Refer to FIGURE 1-2

Manual page 32

200 mV Time Base Output Signal

(    )         Set the Oscilloscope Calibrator’s POWER switch to the ON position.

(    )*       Adjust the oscilloscope trigger and stability control until a trace similar to Figure 1-2 is obtained.

(    )**      Adjust the oscilloscope’s horizontal sweep rate as necessary to the keep the trace visible on the screen.

(    )**      Set the VOLTS OUT switch one position clockwise.

(    )*       Repeat the above two steps ** twice more.

(    )         Set the VOLTS OUT switch to the 1V position.

(    )         Set the MULTIPLIER switch to the X2 position down and repeat the above four * marked steps.

(    )         Set the VOLTS OUT switch to the 1V position.

(    )         Set the MULTIPLIER switch to the X5 position down and repeat the above four * marked steps.

(    )         Set the VOLTS OUT switch to the GND position.

(    )         Disconnect the Oscilloscope Calibrator cable from the oscilloscope’s vertical input.

Square Wave Voltage Output Signal

(    )         Set the VOLTS OUT switch to the 1 mV position.

(    )         Set the MULTIPLIER slide switch to the X1 position.

(    )         Connect the calibrator’s VOLTS OUT terminals to the oscilloscope’s vertical input.

(    )         Adjust the oscilloscope trigger and stability control until a trace similar to Figure 1-2 is obtained.

(    )*       Adjust the oscilloscope’s vertical attenuation switch as necessary to the keep the trace visible on the screen.

(    )*       Set the VOLTS OUT switch one position clockwise.

(    )*       Repeat the above two steps five times more.

(    )         Set the VOLTS OUT switch to the GND position.

(    )         Disconnect the VOLTS OUT from the oscilloscope’s vertical input.

* * * * * * *

CALIBRATION using a Digital Voltmeter

Refer to FIGURE 1-3

Illustration Booklet page 3

(    )         Set the VOLTS OUT switch to the 1V position.

(    )         Set the TIME OUT switch to the DC position.

(    )         Set the MULTIPLIER slide switch to the X1 position.

(    )         Connect the meter’s test leads to the VOLTS OUT terminals.

(    )         Adjust the CAL control R14 on the circuit board until the meter reads exactly 1 VDC.

(    )         Set the VOLTS OUT switch to the GND position.

(    )         Set the Oscilloscope Calibrator’s POWER switch to the OFF position.

(    )         Disconnect the Digital Voltmeter from the Oscilloscope Calibrator’s VOLTS OUT terminals.

(    )         Calibration is complete.

* * * * * * *

CALIBRATION using an Analog Voltmeter

Refer to FIGURE 1-3

Illustration Booklet page 3

(    )         Set the voltmeter scale switch to the 5V position.

(    )         Set the voltmeter function switch to the +DC position.

(    )         Set the VOLTS OUT switch to the 1V position.

(    )         Set the TIME OUT switch to the DC position.

(    )         Set the MULTIPLIER slide switch to the X1 position.

(    )         Connect the meter’s ground test lead to the black VOLTS OUT terminal.

(    )*       Measure and note the voltage reading at TP2 on terminal strip AB, lug 3.

(    )*       Measure the voltage reading at TP1 on the foil side of the circuit board.

(    )*       Adjust the CAL control R14 until both TP1 and TP2 readings are equal.

(    )*       Repeat the above three marked steps several times for accurate readings.

(    )         Set the VOLTS OUT switch to the GND position.

(    )         Set the Oscilloscope Calibrator’s POWER switch to the OFF position.

(    )         Disconnect the Analog Voltmeter from the Oscilloscope Calibrator’s VOLTS OUT terminal.

(    )         Calibration is complete.