SU623166A1 - Device for measuring steepness of field-effect transistor current-voltage characteristic - Google Patents

Description

The exemption relates to the field of radio measurement instrumentation and can be used in the development of instruments for measuring the parameters of field effect transistors.

Devices are known for measuring the parameters of field-effect transistors, including steepness and current-voltage characteristics (IVC). A device made in the form of a meter, whose structure varies depending on the measured parameter, is known. The drawback of the device is the difficulty of the technical implementation of the contradictory requirements for individual measuring nodes Sh.

A device G21 for measuring the parameters of field-effect transistors is also known, which automatically measures the slope of the current-voltage characteristics of the tested transistors.

The known device, which is the closest in technical essence to the one proposed, contains a source of voltage of the drain current, a slope meter, including a voltage generator connected to a terminal for connecting the gate of the tested transistor, and a circuit for measuring the variable component of the drain current connected to The drain circuit of the tested transistor, the drain current converter, the input of which is connected in parallel with the circuit of measuring the variable component of the drain current, and the output with the comparison circuit,

and a controlled voltage source aai the thief, as well as a pflog voltage meter with a drain current sensor and switches.

The disadvantage of the known device

It is impossible to measure the slope of the current-voltage characteristic of a field-effect transistor at a given drain current.

The purpose of the invention is to automatically measure the steepness of the IVC for a given

drain current.

The goal is achieved by the fact that a block for setting the drain current level is inserted into the device, two Ktxroporo outputs are connected respectively to the control panel.

the input of the drain current transducer and the second input of the comparison circuit; and the output of the comparison circuit is connected to the control input of the alternating voltage generator. The device contains a source of drain voltage, through a contact God-2, connected to a drain from an erne norfe transistor 3, generating 4 alternating voltages, through a contact gopo & 2 f connected to the gate of the field-effect transistor 3, the circuit 5 measuring the overflow component of the current line, a unit 6 for ejection of a drain current level, connected in series: a drain current converter 7, a comparison circuit 8, and a controlled source 9 of the gate voltage. The comparison circuit 8 is connected to the control input of the alternating voltage generator 4, and the two outputs of the drain current level setting unit 6 are connected respectively to the control input of the drain current converter 7 and the second input of the drain current level setting 6 provides at its outputs a combination of output signals that control the transfer coefficient of the converter 7 of the drain current and the level of operation of the circuit 8, corresponding to the required value of the drain current. The output signal of the comparison circuit is controlled by changing the value of the output voltage of the source 9 to the gate voltage. Due to the action of the servo system thus obtained, the output voltage of the controlled source 9 of the gate voltage is set such that the drain Tok of the measured yard field-effect transistor 3 corresponds to the specified value. When this condition is fulfilled, the output signal of the comparison circuit 8, which is fed to the control: the alternating voltage generator input 4, allows the generator to work in the steepness direction. In that case, if the DcpDTOBoe voltage is measured, the output of the traeistor changes, for example, under external factors, the output signal of the comparison circuit 8, which indicates the actual value of the current does not match the specified value, prevents the generator 4 AC voltage from working. an event which occurs under the action of the following system. . Thus, regardless of the change in the ps of this voltage (for example, and the cut-off) of the field-effect transistor, the measurement of the steepness is automatically performed at a given drain current. Photo inventive Device for measuring the slope of field-effect transistors, comprising a source of drain voltage, an alternating voltage generator, a measuring circuit for alternating drainage current, a drain current converter, cxeiUy comparison, and a controlled source of surge current, characterized by that, for the purpose of automatic measurement at a given drain current, a block for setting the drain current level was entered, two outputs of which are connected respectively to the control input of the drain current converter and to the second input of the circuit compared to and Yield of which is connected to a control input of the generator AC voltage. Sources of information taken into account in the examination: 1. Dargis A. K., Stankevichus L. L., Zydukas D. D. About building equipment for remote measurement of the parameters of field-effect transistors. Proceedings of the scientific and technical conference Radioelectronics, vol. 7, Kaunas, 1971, p. 143-147. 2. Dargis A.K.Stankevichyus L.L., Eidukas D.D. Issues are automated for the design of field parameters, transistors. Proceedings of scientific and technical confreipin Radioelectronics, t, 8, Kaunas, 1972, p. 306-311.