Product Manual

- 17 -
__________________________________________________________________________
1.6 Operating Program: 23020, 23000, 23040
Single Hearing Level AudioScope continued
Sequence: Cause: Effect:
U4 also selects resistance this resistance is adjusted for the
between pin 17 of U4 output amplitude of the 2000 Hz tone
and pin 5 of U3. only and is used to control output
amplifier U3.
6. Logic pin 3 goes to 0v activates LED (4000 Hz LED.)
U4 pulls pin 1 to 0v selects resistance between pin
7 of U2 and ground.
this charges C5 produces 4000 Hz sine wave at pin 2
of U2
U4 also selects resistance this resistance is adjusted for the
between pin 16 of U4 output amplitude of the 4000 Hz tone
and pin 5 of U3. only and is used to control output
amplifier U3.
7. Logic cycle completes itself Ready LED illuminates
8. Manual switch off unit deactivates, lamps & logic off