Abstract:
An all in one (AIO) computer implemented as a personal computer (PC) or a display includes a high definition multimedia interface, a speaker, and a speaker control circuit. The speaker control circuit includes an earphone interface circuit, a main controller, a signal processing unit, and a signal control circuit. The earphone interface circuit detects whether an earphone is inserted into the AIO computer. When the earphone interface circuit detects the earphone is connected to the AIO computer, if the AIO computer is implemented as the PC, the main controller sends a first muting signal. If the AIO computer is implemented as the display, the main controller sends a second muting signal, and the signal control circuit controls and mutes the speaker according to the first muting signal and the second muting signal.
Abstract:
An indicator light control circuit includes a basic input output system (BIOS) integrated circuit (IC), a microcontroller, a signal control unit, an electronic switch, and an indicator light. The microcontroller includes a general purpose input output (GPIO) pin. When different operating options of the indicator light are set into and by the BIOS IC, the BIOS IC controls the GPIO pin of the microcontroller to output command signals, such as a low voltage signal, a high voltage signal and pulse signals, then the signal control unit generates and outputs signals according to the command signals. Thus, the electronic switch is operated to turn on or turn off or to pulse when controlling the operation of the indicator light(s).
Abstract:
A voltage detection circuit used to detect a voltage source includes a Zener diode, a thyristor, a first resistor, a second resistor, a first light-emitting diode (LED), and a second LED. A cathode of the Zener diode is connected to the voltage source. An anode of the Zener diode is connected to a control terminal of the thyristor through a first resistor. An anode of the thyristor is connected to the voltage source through a second resistor. The anode of the thyristor is connected to an anode of the first LED. A cathode of the thyristor is connected to a cathode of the first LED. The cathode of the thyristor is connected to an anode of the second LED, and a cathode of the second LED is grounded.
Abstract:
An electrical connector assembly includes a male connector and a female connector connectable to the male connector. The male connector includes a male insulating housing and a number of first terminals assembled in the male insulating housing. a protrusion extends up from the top surface of the male insulating housing. The protrusion forms an ejecting surface at a rear side of the protrusion. The female connector includes a female insulating housing and a number of second terminals assembled to the female insulating housing for connecting with the first terminals. a fastening hole is defined in the top surface of the female insulating housing to hold the protrusion therein. The ejecting surface of the protrusion of the male connector is substantially arc-shaped or inclined.
Abstract:
A printed circuit board includes a power layer, a ground layer, a signal layer, and a backboard. The backboard is arranged below the signal layer opposite to the ground layer. A number of vias are formed from the backboard through the signal layer, and then connected to the ground layer.
Abstract:
A fan control system includes a temperature detecting circuit and a rotation rate control circuit. The detecting circuit includes a first amplifier, a second amplifier, and a thermistor. The rotation rate control circuit includes a first terminal, a second terminal, and a third terminal. The detecting circuit detects temperature and outputs a voltage signal. The rotation rate control circuit receives the voltage signal and controls the rotation rate of the fan according to the voltage signal.
Abstract:
An under-voltage warning circuit includes a Zener diode, a transistor, an annunciator, and a thyristor. When the power source is within a certain range, the annunciator does not work. When the voltage level of the power source V_in is lower than the predetermined value, the annunciator works to denote that the power source is under-voltage.
Abstract:
A voltage providing circuit includes a protective circuit and a power supply circuit. The protective circuit includes a first transistor. A first control signal is input to a collector of the first transistor, a second control signal is input to a base of the first transistor, an emitter of the first transistor is grounded. The collector of the first transistor is connected to the power supply circuit. The second control signal and the first control signal jointly control the power supply circuit to be turned on or turned off. When the second control signal is at a low level, the first transistor is turned off and the power supply circuit is turned off. When the second control signal is at a high level, the first transistor is turned on and the power supply circuit is turned on. Thus, the providing circuit can prevent the electronic component from being damaged when a computer is restarted.
Abstract:
A supply voltage switching circuit for a computer includes a chipset, a first transistor, a second transistor, and a third transistor. The chipset includes a first MOSFET and a second MOSFET. A 5V system voltage and a 5V standby voltage are respectively inputted to sources of the first MOSFET and the second MOSFET. Gates of the first MOSFET and the second MOSFET are respectively coupled to collectors of the second transistor and the third transistor. A base of the first transistor is coupled to a terminal for receiving a control signal from the computer. The 5V standby voltage is inputted to a collector of the first transistor. Bases of the second transistor and the third transistor are coupled to the collector of the first transistor. A 12V system voltage and the 5V standby voltage are respectively inputted to collectors of the second transistor and the third transistor.
Abstract:
A voltage stabilizing circuit including an input port, an output port, a transistor, a diode, a three-terminal voltage regulating reference source, a first resistor, and a second resistor. The transistor has a collector terminal and an emitter terminal connected to the input port and the output port, respectively. The diode has an anode connected to the input port and a base terminal of the transistor. The three-terminal voltage regulating reference source has an anode connected to ground, a cathode connected to the input port and a cathode of the diode, and a reference terminal The first resistor is connected between the cathode of the diode and the reference terminal of the three-terminal voltage regulating reference source. The second resistor is connected between ground and the reference terminal of the three-terminal voltage regulating reference source.