Global Specialties PB-503C - Manual - Manual (Page 10)

10
DESCRIPTION OF INDIVIDUAL FEATURES
In order to properly use the full capabilities of the PB-503C, it is highly recommended
that the user become familiar with the panel layout and the features of the components.
(See Figure 1)
POWER SUPPLIES
By combining the three DC power supplies on the PB-503C, the user may work with
virtually any type of integrated circuit or discrete component. The fixed 5 volt supply has
become an industry standard for powering digital IC's. IC's which require +5 V, +12 V,
and -5 V are easily accommodated by the PB-503C. The variable supply output
voltages may be changed by using the screwdriver adjustment on the front panel. The
positive and negative outputs are continuously variable from +1.3 to +15 volts and -1.3
to -15 volts respectively. Both variable supply outputs are referenced to circuit common.
This creates a split supply which is often used with differential and operational amplifiers
(op amps). The adjustments are recessed to prevent inadvertent voltage changes which
could be destructive to a circuit.
In addition to the DC power supplies, the PB-503C also provides a 12.6 volt center-
tapped AC supply. This allows the user to construct any of a variety of half-wave and
full-wave rectified power supplies on the breadboarding area and apply power by simply
connecting jumper wires to the three AC supply output pins.
FUNCTION GENERATOR
The multi-waveform function generator provides continuously variable frequency signals
from 0.1 Hz (for extra-low frequency work) to radio frequency signals of 100 KHz. The
frequency is selected in six decade ranges, with a slide potentiometer to adjust
frequency within each range. The sine wave output is factory adjusted for minimum
distortion. The triangle waveform is adjusted for best linearity. The standard square
wave and TTL level outputs are both set at a 5 0% duty cycle. The TTL output
(available when the function generator is set to Square Wave mode), capable of driving
up to 10 TTL loads, is continuously available and in phase with the square wave output.
The low output impedance of the sine, square, and triangle waveforms (600
Ω) assures
maximum coupling of the output signal to the device being driven. All outputs can
withstand a continuous short circuit to ground.
LOGIC INDICATORS
Sixteen LEDs, eight red and eight green, make up eight Logic Indicators that will display
logic high and low conditions based on either TTL or CMOS thresholds, selectable by
the user. Operating voltage can also be selected by the user to be either at +5 volts, or
at the setting of the 1.3 - 15 volts +V supply. This selection should be the same as the
operating circuitry that is to be monitored. The red LEDs will light when the voltages at
the inputs are 2.2 volts or higher when in the TTL position, or 70% of the operating