A transistor characteristic tracer is a specialized oscilloscope that allows direct observation of various transistor characteristic curves and curve families. For example: the input, output, and feedback characteristics of transistors in common-emitter, common-base, and common-collector configurations; the forward and reverse characteristics of diodes; the voltage regulation or Zener characteristics of Zener diodes; it can measure transistor breakdown voltage, saturation current, alpha or beta parameters, etc.
(1) Y-axis deflection factor:
Collector current range: 0.01 to 1000 mA/div, in 16 steps, error ≤ ±3%;
Collector current multiplier: ×2, ×1, ×0.1, three steps, error ≤ ±3%;
Base voltage range: 0.01 to 0.5 V/div, in 6 steps, error ≤ ±3%;
Base current or base source voltage: 0.05 V/div, error ≤ ±3%;
External input: 0.1 V/div, error ≤ ±3%;
(2) X-axis deflection factor:
Collector voltage range: 0.01 to 20 V/div, in 11 steps, error ≤ ±3%;
Base voltage range: 0.01 to 0.5 V/div, in 6 steps, error ≤ ±3%;
Base current or base source voltage: 0.5 V/div, error ≤ ±3%;
External input: 0.1 V/div, error ≤ ±3%.
(3) Base step signal:
Step current range: 0.001 to 200 mA/div, in 17 steps;
Step voltage range: 0.01 to 0.2 V/step, in 5 steps;
Series resistance: 10 Ω to 22 kΩ, in 24 steps;
Steps per family: 4 to 12, continuously variable;
Steps per second: 100 or 200, 3 settings;
Step action: Repeat, Off, Single family, three settings;
Polarity: Positive, Negative, two settings;
Error ≤ ±5%.
(4) Collector sweep signal:
Peak voltage: 0 to 20 V, 0 to 200 V, two ranges, positive and negative continuously adjustable;
Current capacity: 10 A (average) at 0 to 20 V, 1 A (average) at 0 to 200 V;
Power dissipation limiting resistor: 0 to 100 kΩ, in 17 steps, error ≤ ±5%;
(5) Power supply: AC 220 V ±10%, 50 Hz ±20 Hz.
Power consumption: 260 VA.
Ambient temperature: -10 °C to +40 °C
Relative humidity: ≤80%
The transistor characteristic tracer can be used to measure the input, output, transfer characteristics, and α, β parameter characteristics of transistors in common-collector, common-base, and common-emitter configurations; it can measure various reverse saturation currents ICBO, ICEO, IEBO, and various breakdown voltages BUCBO, BUCEO, BUEBO, etc.; it can also measure the characteristics of diodes, Zener diodes, thyristors, tunnel diodes, field-effect transistors, and digital integrated circuits, making it widely applicable.
The transistor characteristic tracer mainly consists of a collector sweep generator, a base step generator, a synchronization pulse generator, an X-axis voltage amplifier, a Y-axis current amplifier, an oscilloscope tube, a power supply, and various control circuits. The main functions of each component are as follows:
(1) The main function of the collector sweep generator is to generate the collector sweep voltage, which is a sinusoidal half-wave waveform with adjustable amplitude, used to form the horizontal scan line.
(2) The main function of the base step generator is to generate the base step current signal, with adjustable step height, used to form multiple curve families.
(3) The main function of the synchronization pulse generator is to generate synchronization pulses to ensure that the signals from the sweep generator and the step generator are strictly synchronized.
(4) The main function of the X-axis voltage amplifier and Y-axis current amplifier is to amplify the voltage signal (or current signal) taken from the device under test to a level sufficient to drive the display screen, and then send it to the corresponding deflection plates of the oscilloscope tube to form the scan curve on the screen.
(5) The main function of the oscilloscope is to display the test curve image on the screen.
(6) The power supply provides energy for the entire instrument, and the various control circuits facilitate test switching and adjustment.
