ELECTRONIC ENGINEERING TEST QUESTIONS WITH CORRECT ANSWERS

ELECTRONIC ENGINEERING TEST QUESTIONS WITH CORRECT ANSWERS State Ohm's law - ANSWER V=IXR R=V/I I=V/R If current goes down, what does resistance do? - ANSWER Reistance goes up If Voltage is CONSTANT and Resistance goes DOWN, what must Current do? - ANSWER Current HAS to go UP! What is the definition of a short circuit? - ANSWER Zero resistance. Circuit has high current, and zero resistance. What would cause Current to DECREASE in a circuit, IF Voltage remained CONSTANT? - ANSWER INCREASSE in Resistance What is a Transformer? - ANSWER An electrical device that transfers energy from one electrical circuit to another by magnetic coupling, aka: Mutal Induction. One set of windings induce a voltage in the other set of windings. What are Transformers used for? - ANSWER Used to convert between high and low voltages and for impedance transformation. State the Power formula. - ANSWER P = V X I power equals voltage times current What are air core transformers main use? - ANSWER Radio frequency circuits ABOVE 20kHz What are iron core transformers main use? - ANSWER Lower frequency: below 20kHz To transmit electrical power what must a transformer have? - ANSWER Has a very high current OR very high voltage. High current means a high flow rate of electrons. This requires a VERY large COPPER or ALUMINUM cable. *How does a Power Station function? - ANSWER Uses high voltage to reduce the amount and weight and therefore What is the symbol for a transformer? - ANSWER XX What kind of electrical charge does a neutron have? - ANSWER Neutral What kind of electrical charge does a proton have? - ANSWER Positive The step down transformer outside a house does what? - ANSWER Reduces the voltage to a usable voltage for the house ELECTRIC, which are usually TWO 120VAC legs. What is an electronic shunt? - ANSWER A device which allows electric current to pass around a point in a circuit. A shunt as CIRCUIT PROTECTION: is a device that is commonly called a CROWBAR circuit and is used when a circuit must be protected from over VOLTAGE. What does a capacitor do? - ANSWER When used as a shunt, redirects hight frequency nouse to ground before it can transmit to the load or other circuit components. This is why they are used so frequently in DC power supplies as AC filters. What is a Zenner Diode? - ANSWER Voltage Regulator used when devices are sensitive to reverse polarity in a signal to protect a circuit. Also used in a power supply to cause a fuse or other current limiting circuit to open. How does a shunt used as Circuit Protection work? - ANSWER When a shunt detects an over VOLTAGE it causes a short circuit between the power supply and its return lilne, which produces an immediate drop in voltage and a resultant HIGH CURRENT which opens the CURRENT SENSITIVE DEVICE in the circuit usall a FUSE or CIRCUIT BREAKER. What is ESD? - ANSWER ELECTROSTATIC DISCHARGE: a brief an abrupt electric current that flows between two objects at DIFFERENT ELECTRICAL POTENTIALS which is caused by CONTACT, or INDUCED by AN ELECTROSTATIC field. What is a RESISTOR? - ANSWER Electronical device that RESISTS the FLOW of ELECTRICAL CURRENT. Symbol for: ZENNER DIODE - ANSWER x Definition of Zener Diode: - ANSWER Voltage Regulator, typically REVERSED BIASED. If reverse voltage of a circuit is INCREASED the zener begins to LEAK current until the breakdown voltage is where the current INCREASES DRAMATICALLY. Zener diode will CONDUCT to keep the voltage REGULATED. What is LED - ANSWER Light Emitting Diode emits different colors and are made of different semi-conductor materials, and require different energies to light them. The FLAT side of the LED is the NEGATIVE terminal and the LONGER LEG is the POSITIVE lead. What is a DIODE? - ANSWER Conducts electric current very EASILY in one direction and VERY POORLY in the other direction. Allows DC to pass. IF it is FORWARD BIASED it CONDUCTS with a .7VDC drop across it if it is made of SILILCON. .3V if made of GERMANIUM. Also known as a RECTIVIER because it will stop the flow of AC in one direction, creating a PULSATING DC wave or HALF WAVE. In the SYMBOL which looks like an ARROW, the arr