Abstract: An instrument (1) for controlling the temperature of electronic components (20) under test creates a testing environment in an enclosure within which a component contacts directly the active face of a set of back-to-back Peltier cells (50). Heating and cooling of the component (20) under test is readily achieved by controlling the Peltier cells (50) and test components may be easily interchanged using a removable mounting assembly (10, 11, 12, 13). The instrument has the advantages of being small, portable, easy to operate, inexpensive to manufacture and to run, and of producing very little electrical noise.

Abstract: A CMOS DAC with means to avoid leakage current. In one embodiment, the back gates of the CMOS switches are held at -200 mV with respect to the output lines, and the logic low level to the off switch also is set at -200 mV relative to the output lines. In another embodiment, the CMOS switches are ion-implanted. In a still further embodiment, the output lines are held at a potential 200 mV more positive than the P- well of the CMOS switches.

Abstract: A signal-controllable attenuator comprising a 17-bit multiplying-type digital-to-analog converter having an R/2R ladder network to set the bit weights, and controlled by a 6-bit remotely-generated command signal to vary the attenuation in steps of 1.5 dB through a range of 88 dB. The 1.5 dB steps are controlled by a 4-bit code signal responsive to two bits of the command signal. The 4-bit code signal is directed to four successive bit input terminals of the converter. Which four DAC input terminals are selected is controlled by a shifting matrix which shifts the four bits along the DAC input terminals to a position determined by the other four bits of the command signal.