This paper investigates the use of dielectric barrier discharge plasma actuators in low Re flow control applications. Three different actuator geometries have been tested: a conventional design using two rectangular strip electrodes (the linear actuator) that produces a nearly two-dimensional horizontal wall jet upon actuation, and two new designs that render the plasma induced flow in the form of a vertical jet that can be either three-dimensional using an annular electrode array actuator construction the plasma synthetic jet actuator, PSJA or nearly two dimensional using a modified linear actuator construction consisting of two exposed electrodes and one embedded electrode, the L-PSJA. The modification in actuator design can be used to broaden its applicability and enhance the flow control effects. 2-D PIV measurements are used to characterize the operation of these actuators in quiescent flow, a flat plate boundary layer, and flow over a circular cylinder. In quiescent flow, these actuators add momentum to the residual fluid with significant velocity fluctuations. The interaction of the plasma induced flow with a mean flow is shown to vary with the actuator geometry. The PSJA and L-PSJA geometries enhance the penetration of the plasma induced jet as compared to the linear actuator. The actuators act as an active boundary layer trip, the effectiveness of which is seen to decrease with increasing freestream velocity. While the PSJA affects the global flowfield, the L-PSJA and linear actuator affect primarily the near wall region. The linear actuator is observed to be a better configuration for flow control on a circular cylinder as opposed to the L-PSJA.