Question

An SCR (silicon-controlled rectifier) is frequently used as a switch of AC currrent. If you saw a schematic of a circuit of an AC power heater tha SCR controller, so that if the heater was controlled from 0 to 100% single phase, how many SCR's would you typically expect to see in the circuit.

a. one

b. two

c. three.

You see Solid State Relay in a cabinet controlling an AC Circuit. A key difference in troubleshooting this device over a standard contact relay is ...

a. A solid state relay will normally show off -state leakage

b. Measurements will show a on-state voltage drop across the contacts

c. Both a and b.

A photo diode is commonly used as a light sensor. This device functions because.

a. light reduces the forward bias resistance

b. light increases the forward bias resistance.

c. heat from the light cause eletron flow.

A solid state relay is switching 50 Amps. The relay is using Triac whose on -state voltage drop is 2 Volts. The power supply is 120VAC. Using the formula Power = Volts x Amps, calculate the power (heat) that needs to be disipated by this relay when it is conducting.

a. 50 watts

b. 100 watts

c. 10 watts.

Answer 1