In this paper, we report on an experimental analysis of dimension effect on a room-temperature electrical oscillation in a planar device using vanadium dioxide (VO2) thin film. We investigate the variation of the oscillation current (I-O) and frequency (f(O)) due to the variation of the dimension of the VO2 devices, i.e., the length and width of the current channel of the device. For five different VO2 devices with different dimensions, I-o and f(o) are observed at room temperature in a simple circuit composed of a dc voltage source and a standard resistor including one of the VO2 devices. From the experimental investigation, it is concluded that the peak-to-peak amplitude of I-o and f(o) decrease with the increase of the length and width of the current channel. This indicates that f(o) depends on not only the external source voltage but also the device dimension. (C) 2010 Elsevier B.V. All rights reserved.