FIRST SEMESTER quiz CIRCUITS

 

 For all quizs, you may use your book and you may have the motor control circuit pre-built on your board.  In all circuits, you must protect your LEDs with a resistor, hold down all switches with a resistor and ground all unused inputs on ICs in order to gain credit.  All transistors must have their emitter, base and collector properly connected for credit.

 

1. Connect S1-S4 to the motor control circuit so that you can switch a motor on and off by pushing S1 and S2 and reverse the motor by pressing S3 and S4.  SECOND PART- Connect your photo-resistor to the motor control circuit so that when its is covered the motor will turn off.

2. Wire S1 and S2 so that when both switches are pressed an led will light. 

3. Use a transistor to light an LED.  The base of the transistor must be connected to S1.

4. Use two transistors, S1 and S2 so that when either S1 and S2 are pressed, an LED powered by a transistor will light.  The base of each transistors must be connected to a switch.

5. Use two transistors, S1 and S2 so that when S1 and S2 are both pressed, an LED powered by a transistor will light.  When S1 or S2 or pressed separately, the LED should not light.  The base of each transistors must be connected to a switch.

6. Connect S1 and S2 to 6 volts and the inputs of one NAND gate on the 4011.  Show the output of that gate with an LED.  The LED should only turn off when both buttons are pressed.

7. Make a buzzer triggered by darkness. When you place your finger over the photo-resistor, the buzzer should sound.

8. Use the 555 to build a LED flasher.  The LED may not flash more than once a second or less than once every ten seconds.  SECOND PART- Connect the Decade Counter 4017 so that it will count the pulses from the 555.  Connect two LEDs to three outputs of the 4017 so that one LED will flash quickly, followed by a pause and then the other LED will flash more slowly.