The electron temperature in a pulsed high‐&bgr; ( &bgr;≡2&mgr;nkT/B2≊1) plasma is studied as a function of time using a miniature array of 12 planar Langmuir probes. Instead of sweeping the bias voltage on the collectors, each is set at a different voltage corresponding to points along the characteristicI–Vcurve. A fast‐analog multiplexer, together with a computerized data‐acquisition system, allows determination ofTeto within a few percent accuracy, with a time resolution of 1 &mgr;s. The probe is used to study temperature fluctuations and heat transport in a plasma current sheet.