# Maintenance: Create a bulk quote request Introduction to Transformers In iKnow The eleventh lesson in the iKNOW® Electrical Theory for Troubleshooters Library, this lesson presents the basic parts of a transformer and their function. The lesson explains turns ratio and its relationship to a transformer??s input and output voltages. The participant is also cautioned regarding the dangers of improper transformer connections. Wye and Delta Connections In iKnow The tenth lesson in the iKNOW Electrical Theory for Troubleshooters Library, this lesson discusses Wye and Delta configurations and explains the relationship between phase and line voltages in various connections, and demonstrates the application of the formula that shows this relationship. Inductance In iKnow This is the seventh lesson in the iKNOW Electrical Theory for Troubleshooters Library. This lesson builds on the information presented in the lesson, Electromagnetism. Types of induction, phase, and the effect of induction in AC circuits are covered. Three-Phase Circuits In iKnow This is the ninth lesson in the iKNOW® Electrical Theory for Troubleshooters Library. This lesson defines 3-phase AC, describes the components and operating principle of 3-phase generators, and using the formula for frequency, shows how rotor speed and the number of poles is related to frequency. Electromagnetism In iKnow This sixth lesson in the iKNOW Electrical Theory for Troubleshooters Library uses animations and demonstrations to explain the principles of magnetism, including flux density and electromagnetic induction. The lesson also shows how to plot a sine wave using a graph. Parallel Circuits In iKnow This is the fourth lesson in the iKNOW Electrical Theory for Troubleshooters Library. This lesson describes the behavior of voltage, current, and resistance in a parallel circuit. The learner is also instructed in the identification of the series and parallel portions of a series-parallel circuit. Series Circuits In iKnow This is the third lesson in the iKNOW Electrical Theory for Troubleshooters Library. The lesson presents the operation of a series circuit and trains participants in the identification of simple schematic symbols used to represent components in a series circuit. The behavior of current, resistance, and current in a series circuit, and the used of Kirchhoff's Voltage Law to find total voltage are also covered. Introduction to Electricity In iKnow This is the first lesson in the iKNOW® Electrical Theory for Troubleshooters Library. This lesson uses animation to demonstrate atomic structure, electricity, and how a simple circuit operates. The lesson also explains the characteristics of good conductors and insulators. Protective Helmets In iKnow This is the seventh lesson in the iKNOW Electrical Safety Library. This lesson explains the protection provided by helmets, and the proper methods of inspection, wearing and maintaining a helmet.