Electric adapter with display unit

1. An electric adapter configured to be connected between an electric socket and an electric appliance, for indicating a plurality of electrical parameters of the electric appliance, said electric adapter comprising:

a housing;

a plug arranged on a rear of the housing for insertion into an electric socket;

an outlet socket formed on the housing, whereby the electric appliance can be electrically connected to the outlet socket;

a control circuit including a central processing unit located within the housing for detecting a plurality of electrical parameters of the electric appliance during operation

a display unit arranged on the housing for displaying at least one of the plurality of electrical parameters detected by the control circuit; and,

a mode selection switch arranged on the housing and connected to the central processing unit, the mode selection switch being operable from externally of the housing to select which of the plurality of electrical parameters is displayed by the display unit.

2. The electric adapter as claimed in claim 1, wherein the plurality of electrical parameters indicated on the display unit comprises present time, voltage value, current value, watt, kilowatt-hour, apparent power value, and power factor.

3. The electric adapter as claimed in claim 1, further comprising a power on/off switch arranged on the housing and connected to the central processing unit for turning on/off the adapter.

4. The electric adapter as claimed in claim 1, wherein the control circuit comprises:

a voltage detecting circuit for detecting a voltage supplied to the electric appliance and generating a voltage value;

a current detecting circuit for detecting a current supplied to the electric appliance and generating a current value; and

a time base signal generator for providing a time base signal; whereby the central processing unit receives the voltage value generated by the voltage detecting circuit, the current value generated by the current detecting circuit, and time base signal to calculate the plurality of electrical parameters.

5. The electric adapter as claimed in claim 4, wherein the voltage detecting circuit comprises:

a voltage amplifier electrically connected to the output outlet of the adapter in parallel connection for generating an analog-voltage signal;

a voltage zero-crossing detecting circuit for detecting a zero-crossing signal of the analog voltage signal and then sending the zero-crossing signal to the central processing unit; and

an analog-to-digital converter for converting the analog voltage signal generated by the voltage amplifier into a digital voltage value, and then sending the digital voltage value to the central processing unit.

6. The electric adapter as claimed in claim 4, wherein the current detecting circuit comprises:

a current amplifier for detecting a current flow supplied to the electric appliance, and then generating an analog current signal; and

an analog-to-digital converter for converting the analog current signal generated by the current amplifier into a digital current value, and then sending the digital current value to the central processing unit.

7. An electric adapter connected between an electric socket and an electric appliance, for indicating a plurality of electrical parameters of the electric appliance, said electric adapter comprising:

a housing;

a plug arranged on a rear of the housing for insertion into an electric socket;

an outlet socket formed on the housing, whereby the electric appliance can be electrically connected to the outlet socket;

a control circuit arranged in the housing for detecting the plurality of electrical parameters of the electric appliance during operation; and

a display unit arranged on the housing for displaying at least one of the plurality of electrical parameters received and processed by the control circuit, wherein the control circuit comprises:

a voltage detecting circuit for detecting a voltage supplied to the electric appliance and generating a voltage value;

a current detecting circuit for detecting a current supplied to the electric appliance and generating a current value;

a time base signal generator for providing a time base signal; and

a central processing unit receiving the voltage value generated by the voltage detecting circuit, the current value generated by the current detecting circuit, and the time base signal for calculating the plurality of electrical parameters, wherein the voltage detecting circuit comprises:

a voltage amplifier electrically connected to the output outlet of the adapter in parallel connection for generating an analog voltage signal;

a voltage zero-crossing detecting circuit for detecting a zero-crossing signal of the analog voltage signal and then sending the zero-crossing signal to the central processing unit; and

an analog-to-digital converter for converting the analog voltage signal generated by the voltage amplifier into a digital voltage value, and then sending the digital voltage value to the central processing unit.

8. The electric adapter as claimed in claim 7, wherein the plurality of electrical parameters indicated on the display unit comprises present time, voltage value, current value, watt, kilowatt-hour, apparent power value, and power factor.

9. The electric adapter as claimed in claim 7, further comprising a power on/off switch arranged on the housing for turning on/off the adapter and a displaying mode selection switch arranged on the housing.

10. The electric adapter as claimed in claim 7, wherein the current detecting circuit comprises:

a current amplifier for detecting a current flow supplied to the electric appliance, and then generating an analog current signal; and

an analog-to-digital converter for converting the analog current signal generated by the current amplifier into a digital current value, and then sending the digital current value to the central processing unit.

11. An electric adapter connected between an electric socket and an electric appliance, for indicating a plurality of electrical parameters of the electric appliance, said electric adapter comprising:

a housing;

a plug arranged on a rear of the housing for insertion into an electric socket;

an outlet socket formed on the housing, whereby the electric appliance can be electrically connected to the outlet socket;

a control circuit arranged in the housing for detecting the plurality of electrical parameters of the electric appliance during operation; and

a display unit arranged on the housing for displaying at least one of the plurality of electrical parameters received and processed by the control circuit, wherein the control circuit comprises:

a voltage detecting circuit for detecting a voltage supplied to the electric appliance and generating a voltage value;

a current detecting circuit for detecting a current supplied to the electric appliance and generating a current value;

a time base signal generator for providing a time base signal; and,

a central processing unit receiving the voltage value generated by the voltage detecting circuit, the current value generated by the current detecting circuit, and the time base signal for calculating the plurality of electrical parameters, wherein the current detecting circuit comprises:

a current amplifier for detecting a current flow supplied to the electric appliance, and then generating an analog current signal; and

an analog-to-digital converter for converting the analog current signal generated by the current amplifier into a digital current value, and then sending the digital current value to the central processing unit.

12. The electric adapter as claimed in claim 11, wherein the plurality of electrical parameters indicated on the display unit comprises present time, voltage value, current value, watt, kilowatt-hour, apparent power value, and power factor.

13. The electric adapter as claimed in claim 11, further comprising a power on/off switch arranged on the housing for turning on/off the adapter and a displaying mode selection switch arranged on the housing.