دارة تكامل ميلر (Miller) لدارة الإنحراف الرأسية .. كتاب التلفزيون الملون والعادي

14-6 Miller integration circuit for the vertical deviation circuit:

It is a modern circuit used in some types of television receivers - in the stage of vertical deviation, and it differs from the other circuits, which have been previously explained. C1 in the integration circuit in a special way. To realize this method, we must return to the principles of capacitor charging. In order to achieve a sawtooth voltage with a linear wave on both ends of the capacitor, the charging current of the capacitor must be constant. It is linear - although there is some bending towards its top, and since it will be a non-linear sawtooth, which requires the presence of some additional elements in the vertical circuit to compensate for the non-linearity of the sawtooth and to correct other factors that disturb the linearity of the vertical scan. This is done by controlling the vertical linearity control element. Because a Miller integrator gives a linear vertical sweep that causes the technical advantages of the design, it does not require any vertical linearity tuning.

The charging current stability:

The charging current must be constant in order for the sawtooth wave to be linear, and this is achieved in only one way, which is to make the grounded end of the capacitor C1 change its voltage in the opposite direction and with the same page and amplitude of the variable voltage on the charging end of the capacitor as in the figure - that is, when the voltage rises on the left side For capacitor C1 in the positive direction, the voltage at the right end of this capacitor drops in the same proportion. Voltage from the saw on the right and left side of the capacitor C1 are of opposite polarity, and this is what is added to each other in the capacitor - in fact, the negative sawtooth wave on the right end of the capacitor is added to the source voltage and provides the capacitor with a voltage that increases at the same rate as the formation of the saw - and the result is the production of Constant current on C1 is more than the normal, low current original circuit
The capacitor, and this constant current passing through C1 during the normal charging period - forms a linear sawtooth wave at its ends, and this wave is used to operate the deflection coils after passing through several amplification stages) and the vertical output transformer. The vertical one - designed by the American RCA company - and can be made in the form of an integrated circuit (IC) with one chip and 14 connecting poles.

14-7 Oscillator circuit and vertical deviation in the Seronix device (270 SR):

This vertical oscillator is of the unstable multivibration type (Fig. 14-9) consisting of transistors T451 and T452. This oscillator is synchronized with vertical pulses applied to the base of T451 through the integration circuit (451 C452) and (C461). These pulses come from IC501, socket No. (7), and the oscillator frequency is controlled by the variable resistance R427, and the vertical amplitude is controlled by the resistance R461, which controls the amplitude of the pulses in the oscillator output, and a change in the value of the oscillator feed voltage. The output of the multi oscillator gives the pulses to the base of the transistor T453 which also receives comparator pulses from the vertical deflection coils, through the resistor R467, to ensure the automatic control of the frequency, and this transistor amplifies the voltage of the pulses after comparing them with the pulses coming from the vertical oscillator stage. and pulses of the deflection coils - and gives the new frequency to the vertical output that consists of two transistors 454 T455, push-pull type - and they enlarge the power to operate the vertical deflection coils - which direct the electronic beam in vertical scanning - and it is worth noting that the diode Zenir D425 protects the output transistors of the amplification stage From an increase in the supply voltage (48) volts, this diode is in the form of a short circuit when the voltage rises between its two ends, and thus secures the protection of the circuit elements