Abstract: A voltage indicator circuit for indicating a charge state of a power supply, such as a battery pack, is disclosed. The voltage indicator circuit includes a voltage divider circuit that connects to a plurality of series connected light sources, such as light emitting diodes. Upon activation of the voltage divider circuit, one or more of the light sources may illuminate to provide a visual indication of the current charge state of the power supply. More particularly, the number of light sources illuminated varies according to the charge state of the battery pack.

Abstract: A voltage indicator circuit for indicating a charge state of a power supply, such as a battery pack, is disclosed. The voltage indicator circuit includes a voltage divider circuit that connects to a plurality of series connected light sources, such as light emitting diodes. Upon activation of the voltage divider circuit, one or more of the light sources may illuminate to provide a visual indication of the current charge state of the power supply. More particularly, the number of light sources illuminated varies according to the charge state of the battery pack.

Abstract: A battery charger is adapted to increase a charge current applied to at least one battery from a predetermined supply voltage. The charger includes a supply voltage generating device coupled to an AC voltage source for generating the predetermined supply voltage and a charging circuit electrically connected to the supply voltage generating device. The charging circuit includes a first capacitor and a second capacitor AC coupled to the first capacitor. The charging circuit is adapted to apply the charge current from the supply voltage generating device to the at least one battery through the first capacitor during a first half of a charging cycle, and store the charge current from the supply voltage generating device in the second capacitor during a second half of the charging cycle.

Abstract: A multiple frequency horizontal scan system includes a scan frequency compensation system which detects horizontal scan frequency changes by frequency detecting the horizontal sync pulses. A frequency responsive switching system couples the appropriate reactive components to the horizontal defection yoke and horizontal output transformer in response to sync pulse frequency. The system further supplies alternative voltages for the scan system operating supply in response to horizontal sync pulse frequency. In addition, the system provides a convenient source of frequency dependent switching signal which may be utilized to operate additional auxiliary elements in response to changes of horizontal scan system frequency.

Abstract: A display monitor includes a conventional cathode ray tube display together with conventional display drive circuitry. Vertical and horizontal deflection systems are operative to provide raster scanning of the cathode ray tube. High voltage apparatus produce the required CRT beam accelerating potential. A scan modulator is coupled to the horizontal deflection system and is operative to provide stable control of the amplitude of horizontal deflection signal. A modulator drive control responds to the amplitude of horizontal deflection signal and produces a control signal utilized by the modulator in maintaining stable horizontal scan amplitude. A scan selection network is coupled to the modulator drive control to selectively alter the operating point of the scan modulator and thereby produce different scan widths for normal and expanded view operation.

Abstract: A display monitor includes a conventional CRT and associated display drive circuitry together with conventional horizontal and vertical deflection systems. A high voltage system is operated in response to the horizontal deflection system to produce a CRT accelerating potential. A display size control responds to changes of high voltage system current to produce an error signal which is used to produce compensating amplitude changes of vertical and horizontal deflection currents in order to maintain substantially constant image size.

Abstract: A display monitor includes a conventional cathode ray tube display and display drive. A conventional horizontal deflection system and high voltage system are operable to provide horizontal scan of the cathode ray tube and a high voltage potential therefor. A vertical deflection system suitable for multiple frequency and normal or expanded modes of operation includes a vertical oscillator and vertical amplifier driving a vertical deflection yoke. A sample of the vertical deflection signal is detected by an amplitude detector and compared to a reference amplitude to produce an error signal operative upon the vertical scan system. Individual reference voltages corresponding to normal and expanded modes of operation are selectively coupleable to the reference voltage portion of the system by a selector switch.

Abstract: A temperature compensated G2 grid drive circuit for use with a video display having a high voltage section supplying a high voltage signal to a cathode, filament and G2 grid of a CRT, wherein the high voltage section has a negative temperature coefficient, includes an input terminal for receiving the high voltage signal and a temperature compensating circuit coupled between the input terminal and the G2 grid of the CRT. The temperature compensating circuit is characterized as having a slightly positive temperature coefficient for maintaining the brightness of the video display substantially constant by driving the G2 grid for compensating for variations with temperature in the high voltage signal supplied to the cathode, filament and G2 grid.