InterAct Accessories 4040A

OPERATING INSTRUCTIONS

OUTPUT PROTECTION CONSIDERATIONS

Use care when connecting the function generator output to a

signal injection point. Excessive voltage at the point of signal

injection of the function generator can cause internal damage.

Under normal operation, the generator output should never be

connected to an external voltage other than low dc values that can

be matched with the DC OFFSET control. The Model 4040 is

overload protected so that shorting the output, even continuously,

will not cause damage. A fuse has been added in series with the

OUTPUT jack to help protect the instrument from damage by

connection to excessive external voltage.

Damage of this type usually occurs by accidentally connecting

the output of the function generator to a voltage in the equipment

under test. The following protective measures are strongly

recommended:

The user should understand the equipment under test well

enough to identify valid signal injection points (e.g., the base of a

transistor, a logic input of a gate, etc.). The voltage at valid signal

injection points is rarely high enough to damage the instrument.

If in doubt about the safety of a signal injection point, measure

the voltage present at the intended point of signal injection before

connecting the function generator output to that point.

When applying the main output of the function generator to a

circuit point containing a dc level, adjust the DC OFFSET control

so that the dc level at the main output matches the circuit voltage.

Connect the TTL output only to TTL-level circuits. Connect the

CMOS output only to CMOS circuits. Measure the Vcc of the

ure 7. Circuit for Protection of TTL Out

ut.

circuit under test and adjust the CMOS LEVEL control

as instructed in the manual.

When the function generator is used by students or other

inexperienced users, the circuit shown in Fig. 7 could be

added into your TTL output probe or test clip set. It will

protect the TTL output of the generator against external

voltages up to ± 20 volts.

FUNCTION GENERATOR APPLICATIONS

GUIDEBOOK

B+K Precision offers a “Guidebook to Function

Generators” which describes numerous applications for

this instrument, including hook-up details. It also includes

a glossary of function generator terminology and an

explanation of function generator circuit operation. It

maybe downloaded for free off our website at