In conjunction with a dual-trace oscilloscope, the HAMEG HZ65 Component Tester can be used to test semiconductor components, resistors, capacitors and inductors not only off-circuit, but also often without desoldering them from printed circuit boards. Within certain limits, the testing of an integrated circuit is also possible. The transistors can be connected to two 3-point sockets; all combinations of 2 contacts can be selected using a switch for testing.
This simplifies the testing of different transistor pinouts (base-emitter, emitter-collector, base-collector). Components with larger diameter legs and integrated circuits are connected to two banana plugs on the side of the HZ65 using 2 test leads. The direction of current flow through the component under test or IC can be reversed. The HZ65 component tester is particularly essential for repairing devices, providing good or bad information in seconds. It also allows a quick comparison of the unit under test with a known good component.
On some recent devices, the component tester is even integrated as standard.
The Tests page shows different figures with tested components.
- An open circuit is represented by a horizontal line.
- A short circuit is represented by a vertical line.
If the component is a pure resistance, the voltage and current are in phase. The test figure is an oblique straight line.
The value of the resistance determines the angle of inclination. High resistance values give a trace close to horizontal and low values give
a trace close to vertical.
Resistances between 20Ω and 4.7kΩ can be evaluated. The evaluation of resistance comes from experience or a direct comparison with a known component.
Capacitance and inductance test
Capacitors and inductors cause a phase difference between the current and the voltage, thus generating an ellipse. The angle and opening of the ellipse depends on the component impedance at 50Hz.
A horizontal ellipse indicates high impedance, low capacitance, or relatively high inductance. A vertical ellipse indicates low impedance, high capacitance, or relatively low inductance.
A tilted ellipse results from a high resistance added to a reactance. Normal or electrochemical capacitance values from 0.1μF to 1000μF can be obtained approximately.
Accurate measurements can be made by comparison with a known capacity. Inductive components such as coils, transformers, can also be tested.
Determining the value of an inductor is more difficult because of the series resistance. However, the value of the impedance of a choke (at 50Hz) can easily be obtained and compared in the range of 20Ω
Most semiconductors such as diodes, Zener diodes, transistors and field effects can be tested. The figure obtained depends on the type of component (see below).
The main characteristic of semiconductors is non-linearity. It gives the screen two segments which form an angle. It should be noted that direct and inverse characteristics are visualized simultaneously.
This test is only for two pins, so the gain test of a transistor is not possible. Since the applied test voltage is low, all junctions of most semiconductors can
be tested without damage. Therefore, testing of blocking voltage or reverse voltage of high voltage semiconductors is not possible. In many cases, only an open or closed circuit test is sufficient.
The plot of diode characteristics exhibits angulation. The plot for high voltage diodes is different because these diodes are made up of several diodes put in series.
It is possible that only part of the feature is visible. Zener diodes have two bends, a bend close to 0V, and a bend showing the Zener voltage.
Zener voltages greater than 10V cannot be viewed.
The polarity of an unknown diode can be identified by comparison with a known diode.
The following tests can be performed on transistors: emitter base, collector base and emitter collector. The test figures are shown below.
The equivalent circuit of a Zener diode is the connection in series of several normal diodes. There are three different test figures:
For a transistor, the BE and BC figures are important. Figure EC is variable; a vertical line shows a short circuit.
These figures are identical with most transistors except with Darlington and FET . The component tester can distinguish a PNP transistor from an NPN transistor .
When in doubt, comparison with a known component is useful. A connection reversal causes the figure on the screen to rotate 180 °.
In many cases circuit testing is possible. The figures obtained are not classified because they depend on the set of components at the two test points.
Thus, the figure obtained may be different from that obtained with an isolated component. If in doubt, desolder the circuit component. Put the component directly on the sockets of the component tester
to avoid humming phenomena.
It is also possible to proceed by comparison with a circuit in working order, taking the same precautions as for the circuit to be tested.