Relay Logic Relay Logic Basic Relays o A

Relay Logic

Basic Relays o A relay is an electronic control switch used to open or close a mechanical contact whenever a voltage is applied to its coil.

Basic Relays o A basic relay usually contains two sets of contacts, normally open and normally closed. The schematic will show the normal contact position for a de-energized coil. Normally Open Contact Normally Closed Contact

Relay Labeling o o Always look at the relay case to identify the coil, coil voltage, max current, NO and NC contacts. Labeling is always shown in a de-energized state. NC Coil Common NO Contacts

Simple Relay Logic Ckt. Which LEDs will illuminate in this circuit with switch 1 open? With switch 1 closed?

Sump Pump Relay Circuit 120 VAC PUMP To Sump Probes What happens when the sump is wet? What happens when the sump is dry?

NAND – Burglar Alarm

Relay Logic? (AND, OR, NAND, NOR)

Complete the ckt (AND gate)

Complete the ckt (OR gate)

Complete the Truth Table

Complete the truth table

Motor Starter Circuit

Submarine Muzzle Hatch Ckt K-1 -A K-2 -C K-3 -A K-4 -B K-6 K-5 -A K-6 -G K-1 = Submarine Surfaced K-2 = Sea Pressure Equalized K-3 = Speed < 5 knots K-4 = Muzzle Hatch open K-5 = Missile Emergency K-6 = Start opening Muzzle Hatch Open Hatch Switch