Equipment information

Boonton Electronic 190-A Miernik poziomu
Q Meter


The Boonton Radio Corporation Model 190-A Q Meter operates in the vhf range, giving direct-reading measurement of Q values. A front-view photograph of the instrument appears in Figure I1I-1, showing the indicating meter, connection terminals and operating controls. Both the capacitance of the measuring circuit anti the operating frequency are dial-indicated, making possible the calculation of various values of X, R, L, and C of a component under test. A summary of the characteristics and specifications of the Model 190-A is given in Section II. The indicating meter is parallax-corrected to gi c precise readings by means of a blade-type meter needle and a mirror on the meter face. Three scales, in addition to the normal Q scale, read XQ, aQ and LO Q. The multiplier (XQ) scale extends the range of measurable Q values and may be used in conjunction with any of the other scales. The aQ scale directly indicates the difference in Q between two circuit conditions, eliminating calculations, while the expanded LO Q scale permits accurate reading of Q values below 100. Any one of these three scales is read by pressing the respective key switch, located below the indicating meter. Also located under the meter dial are the Q Zero and XQ Zero potentiometer controls, used for electrical zeroing of the meter needle, and the SET XQ knob, which adjusts the output of the internal Oscillator and permits the use of any multiplier value shown on the XQ Scale. The FREQ. RANGE switch and the MC knob and associated dial, at the left side of the instrumental panel, accurately control and indicate the frequency of the Oscillator. At the upper right corner of the panel are the Q capacitor knob and MM1D dial. This knob drives the variable capacitor used in the Q measuring circuit and the dial permits direct-reading of its capacitance. The aQ BALANCE controls, located in the lower right corner of the instrument panel, enable the operator to zero the needle of the indicating meter on the aQ scale when measuring small differences in Q. The outer knob, directly driving the dial, is the coarse balancing control, while the inner knob gives verniet adjustment. A power switch is provided at the extreme lower right and the pilot lamp (lower left) lights when the instiununt circuits arc. energized. Four binding-posr terminals near the right front corner ol the cabinet top permits external components to be connected to the measuring circuit. Inductors which can be resonated in the frequency range of thr Model 190-A are connected directly across the COIL terminals for Q measurement. Small capacitors and certain other components arc connected to the CAP. terminals, and measure in conjunction with stable inductors. The high and low potential COIL terminals and the high and ground potential CAP. terminals are clearly labeled. An accessory set of stable reference coils, the Type 590-A inductors, is available for use with the BRC Model 190-A Q Meter. These specially-constructed coiis permit checking instrument operation and are employed in the Q measurement of components other than inductors. The Model 190-A Q Meter may be used only on a 60-ecle a-c power source. Lor 50 cps operation, the Model 190-AP Q Meter, available on special order, must he used. This model may be operated on either 50-cycle or 60-cycle power lines, but does not provide internal regulation of line voltage. It is recommended that the user employ external regulating facilities to avoid the inconvenience of possible zero shifts and variations in the Oscillator output caused by line irregularities. Without regulation, the accuracy of the instrument is only slight I)' impaired.

show more

Serwis i User Manual
Manual type:
Serwis i User Manual
981.96 Kbytes (1005523 Bytes)
Skanowany dokument, czytając częściowo źle, nie częściowo czytelny.
Upload date:
22 January 2017

Dodaj Komentarz

* Wymagane


Brak komentarzy, bądź pierwszy!