A hydrocarbon bearing formation which is heated using a variable frequency capacitive radio frequency dielectric heating in situ process. The mailbox is supported from an upright support post or structure by one or more expandable and bendable spring units. Such sensing devices further include a feedback loop coupled between a precharge path and the input node of the sensing device. The slurry is then transferred to a cleaning and separating apparatus, where it is separated into liquid and solid components. Then, supporters and transmission lines are formed in the supporter patterns and transmission line patterns, respectively. The CRT display apparatus provides for normal operation of a system while protecting circuit components from abnormal operation of the system.