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Circuit description
21
2. Working
The circuit employed in the GM 5605 is shown in Fig. 13.
If no trigger signal is applied, the potential on the control grid of valve
B501' is determined by the cathode voltage of valve B503. The voltage
across the time base capacitor (C505... C516) is then almost equal to
this cathode voltage, which amounts to approximately 100 V.
As soon as a trigger voltage is applied, valve B503 is made non-conductive
by the positive trigger pulses at the cathode of B503. Owing to the repeti-
tive switching action, the condition of the multivibrator changes into
B503' conductive and B503 cut-off. Now the potential of the control
grid of B501' is undefinite, but in principle will tend to rise to the anode
potential of valve B501'. However, the time base capacitor does not
allow a sudden voltage rise, but will be charged in accordance with an
e-power curve. Owing to the charging, the control grid potential of valve
GR503
91 B503
R531
C505.,
C516
C518
- - -
B501
Fig. 13. Circuit diagram of the "bootstrap" integrator
PEM291
E 132
B501' will rise a little, as a result of which the cathode potential rises to
the same extent. This voltage rise is applied to the cathode of diode
GR503 via capacitor C518, so that the diode is cut-off. The voltage across
resistor R531 + R533 thus remains constant.
If the voltage across the time base capacitor rises further, the process
described will be continued. The time base capacitor is thus charged by
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