Abstract: A two-terminal switch circuit (1) for periodically energizing a load (20) from a voltage supply includes a controllable switch (4) connected between the switch terminals (2,3), a resistance (8) and a capacitor (9) connected in series between the terminals (2,3), and a voltage threshold responsive arrangement (26) having a hysterisis characteristic. The voltage threshold responsive arrangement has a signal input (27) and a power supply input (29) connected to the common point (12) of the resistance and the capacitor, and a signal output (28) connected to a control input (13) of the controllable switch. The voltage threshold responsive arrangement is powered by the capacitor voltage. The threshold responsive arrangement closes the switch when the capacitor charges to a first threshold voltage and opens the switch when the capacitor thereafter discharges to a second threshold voltage which is lower than the first threshold voltage.

Abstract: A two-terminal switch circuit (1) for inclusion in series with a load (20) across a voltage supply (63) for periodically energizing the load (20) from the supply (63) comprises a controllable switch (4) connected between the terminals (2,3), a resistance (8) and a capacitor (9) connected in series between the terminals (2,3), and a voltage threshold responsive arrangement (26) the output signal/input signal characteristic of which exhibits hysteresis. The voltage threshold responsive arrangement (26) has a signal input (27) connected to the common point (12) of the resistance (8) and the capacitor (9), and a signal output (28) connected to a control input (13) of the controllable switch (4). A power supply input (29) of the voltage threshold responsive arrangement (26) is also connected to the common point (12) of the resistance (8) and the capacitor (9) so that the voltage threshold responsive arrangement (26) is powered from across the capacitor (9).

Abstract: A deflection circuit includes a deflection correction circuit (Vs) with a controllable active voltage source (Vs) arranged in a loop formed by a deflection coil (Ld), an S-capacitor (Cs), and a flyback capacitor (Cf). The voltage source (Vs) receives a further power supply voltage (Vb2) and a modulating signal (M) to supply a modulating voltage (Vm) varying in response to the modulating signal (M). The active voltage source (Vs) includes a switching element (S2) which is switched on and off with a frequency which is substantially higher than the deflection frequency to to enable waveforms of the modulating voltage (Vm) with a frequency content which is substantially higher than the deflection frequency such that any desired waveform can be generated within the deflection period (Td).

Abstract: A switching device for S correction capacitors includes parallel-arranged branches, each having a series arrangement of an S correction capacitor (Cs) and a switch (S). At one side, the parallel branches are coupled to a horizontal deflection coil (Lh). The switches (S) are controlled by a microcomputer (13) for switching S correction capacitors (Csi) parallel in dependence upon a repetition frequency of horizontal synchronizing pulses (Hs). A hardware frequency detector (11) supplies frequency information (V) related to the horizontal synchronizing pulses (Hs). A frequency change detector (12) coupled to the hardware frequency detector supplies an attention pulse (AP) to an interrupt input (INT) of the microcomputer (13) when a change of the frequency information (V) has been detected.

Abstract: An electric voltage generator comprises a transformer (1) having a ferromagnetic core (3), a primary winding (5) and a secondary winding (7). The primary winding (5) includes a first primary coil (31) wound in the form of a solenoid and the secondary winding (7) includes a first secondary coil (33) wound in the form of a solenoid. These coils (31, 33) have the same length, have the same number of turns of wire of the same diameter, and are concentrically disposed on the core (3) in the same axial position. Their winding sense and connection to a primary circuit (9) and a secondary circuit (19), respectively, are chosen so that correspondingly situated ends of these two coils carry alternating voltages of the same polarity in the operating condition. Consequently, correspondingly situated turns of the two coils carry the same alternating voltage and interference signals cannot be transferred via the parasitic capacitance (37) between the primary winding (5) and the secondary winding (7).