Abstract: Apparatus and method for trimming pine trees. The device comprises an enclosure having a pair of cutter heads mounted thereon each cutter head a pair of jaws having cutting blades thereon which jaws surround the trunk of the pine tree and then delimb the pine tree as the enclosure is moved up and down the pine tree by being placed on the front of a motorized skid steer loader/lift. The enclosure contains an air compressor driven by an internal combustion engine which supplies air for conveyance to air cylinders operated by a solenoid which cause the cutter head blades to operate. The enclosure can be moved about easily and conveniently by being mounted on the front of the motorized lift such as a caterpillar or forklift-type device.

Abstract: A comparator circuit in accordance with the present invention includes a first stage which is a standard CMOS implementation of a differential amplifier. The differential outputs of the first stage are applied to the inputs of a second differential amplifier stage which is of the same design as the first stage. A hysteresis element is added to the current mirror load of the second stage and is driven by an output of the second stage. This second stage output is applied to a threshold matching single-ended gain stage. The output of the gain stage is applied to a standard CMOS inverter which provides the final comparator output. The hysteresis element is placed internally within the second stage to be driven by the second stage output such that the voltage difference between the differential inputs to the second stage must exceed a preselected threshold voltage before the output to the single-ended gain stage switches state.