The 3 Most basic principles behind hydraulics are:1.) Liquids are incompressible2.) Liquids transmit pressure in all directions and with equal force at right angles to all surfaces3.) Liquids under pressure follow the path of least resistance
Think of voltage as electrical pressure; amperage as the volume of electricity flowing; and resistance as electrical friction that resists current. Direct Current or DC is electricity flowing from a battery. Alternating Current is electricity flowing from an alternating power source such as a stator.
Measuring resistance can indicate the health of a component. For example we can determine if an ignition coil is healthy or not by measuring the resistance of its windings. To measure resistance, set your meter to Ω ohms resistance. If you need to select a range, select the smallest range normally 200 ohms. Place the red probe onto one of the small terminals of the ignition coil, and the black one on the remaining small terminal. Your resistance will then display. A normal ignition coil should read about 3.5 to 4 ohms. If your meter reads a much higher resistance it means your ignition coil may have a short and is faulty.
The hydraulic system begins with the reservoir. This reservoir contains the oil used in the system. Oil is delivered from the reservoir to the hydraulic pump. From there the oil flows to the hydraulic control valve. Once activated, the valve will allow oil to flow to and from the hydraulic cylinder. At the same time, oil is moved from the cylinder back to the reservoir where the cycle repeats.