المنظم بطريقة القاطع .. كتاب التلفزيون الملون والعادي

9-12 Switching Regulators:

The serial transistor voltage regulator is called the linear regulator (Fig. 5 to 100 kHz), and this regulator is used when a small size and high output is required, as this circuit is in a fully open or fully closed position, and this is what reduces its temperature more than a linear regulator, within a wide range of input and outlet voltages and currents. The linear regulator has to spread heat (230 watts), so the regulator by the similar cutter method has to spread only (30 watts). Its circuit can be made on a single silicon board, as in the three-party regulator. If the regulation circuit has a high current, this can be achieved by adding an external serial-pass transistor circuit.

The regulation circuit using the circuit breaker method is used to obtain a voltage (+110 volts) to feed some TV sets. A thyristor (SCR) can be used as a cutting element in a serial transistor regulation circuit.

12-10 black and white transistor TV supply circuit:

The solid-state television set requires less effort than the old LED device. But its current is higher because transistors have low impedance. Some devices operate on DC voltages of 6 volts or 12 volts, and this is what makes them also operate on batteries or car accumulators. Figure 12-14 shows a typical low-voltage circuit that works with alternating current or with a battery and the switch is on and off. A third position is the position of charging the internal batteries without operating the device. It is also charged during the operation of the television set and also works as a voltage regulator circuit when operating normally. As for the resistance (100 ohms), it works. Limit the charging current to the recommended value. Time is an element in the filter circuit (RC). As for the resistance (10 ohms), it determines the charging current of the capacitor within the safe regular value of the diodes (2070 IN).

DC constant low and high voltages

​​​​​Some TV sets with solid elements use low continuous voltages, and others that are high for the transistor circuits in them - and this requires the presence of three or four rectifier and filter circuits, and in the diagram shown in Figure (12-15) we find that the resulting voltages They are (24 V) and (20 volts) used to operate most of the low-voltage stages of the device. A zener diode is used to regulate (+24 V), and a serial pass regulator to regulate the voltage (-20 volts). As for the voltage (+100 volts) required for the image output stages - Vertical - horizontal and sound has its own rectification and filtering circuit - and in some devices the diode may be attached to the metal body of the device assuming the spread of heat, and there may be no insulation between the diode metal and the metal body.
11-12 Hybrid color TV feeder circuit:

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ ​​​​​​​​​​​​​​​​​​​​​​​​​ measurement.

Most of its transistors are fed with a voltage of 20 V, organized in a serial-pass transistor regulation circuit, and the voter is fed with the same voltage + 20 V, but with extra filtering quality - and the resistance R adjusts the voltage + 20 volts - while the second coils of the transformer feed the valve heaters with a voltage of + 20 volts. and effort
(290) F, then the demagnetization coils are fed in series with + B, and the varistor (VDR) and the thermistor (NTC) control the feeding of the magnetization coils (refer to the circuit in a (previous) chapter). The result is a current flowing in the demagnetizing coils for a few seconds before heating the device. A very weak current continues to pass through these coils during the operation of the device. It is worth noting that the screen valve heater is biased with a voltage (140 volts) to prevent short circuits between the heater and the cathode. As for the capacitors, they are parallel microfarads with The diodes are for transient protection and make the diodes in the rectifier circuits have a longer life.In some devices, the diode may be damaged directly when this capacitor is disconnected.