Month: January 2010

PWM Dimming for LED RGB Video Displays

This is an application that can be used to adjust LED brightness while maintaining superior color quality. This application uses pulse width modulation (PWM) dimming technique. This application can be used for single-line scrolling displays, transportation road signs, simple scoreboards, ever-expanding advertising markets encompassing convenience gas stations, shops, stadiums, and stores. Following figures shows color shift caused by analog dimming, […]

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Category: Lighting Tags: ,

HI-FI Tone Control Circuit (High Z Input)

This is a HI-FI tone control circuit with high Z input. This circuit is used to control HI-FI tone. Here is the circuit: To buffer op-amp operated feedback type tone control circuit, this circuit uses 2N3684 JFET. The 2N3684 JFET is implemented on this circuit because it has low noise characteristics and provides the function of a high input impedance. […]

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Category: Audio Tags:

FET Cascode Video Amplifier

This is a simple  FET Cascode Video Amplifier circuit. This circuit has some features, they are reduction of feedback to almost zero and very low input loading. Here is the circuit: This circuit uses 2N3823 because it has high Yfs and low capacitance. RL and load capacitance limits bandwidth of the amplifier. [Source: National Semiconductor Application Note]

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Category: RF and Video Tags:
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