1
1-61 Model 78
ELECTRICAL
Standard Resistance Range, Ohms 10 to 2Meg
Standard Resistance Tolerance ±10% (<100 Ohms = ±20%)
Input Voltage, Maximum 300 Vdc or rms not to exceed power rating
Slider Current, Maximum 100mA or within rated power, whichever is less
Power Rating, Watts 1.0 at 70°C derating to 0 at 125°C
End Resistance, Maximum 2 Ohms
Actual Electrical Travel, Turns, Nominal 22
Dielectric Strength 500 Vrms
Insulation Resistance, Minimum 1,000 Megohms
Resolution Essentially infinite
Contact Resistance Variation, Maximum 1% or 1 Ohm, whichever is greater
ENVIRONMENTAL
Seal 85°C Fluorinert® (No Leaks)
Temperature Coefficient, Maximum ±100ppm/°C
Operating Temperature Range –55°C to +125°C
Thermal Shock 5 cycles, –55°C to +125°C (1% ∆RT, 1% ∆VR)
Moisture Resistance Ten 24 hour cycles (1% ∆RT, IR 1,000 Megohms Min.)
Shock, 6ms Sawtooth 100G’s (1% ∆RT, 1% ∆VR)
Vibration 20G’s, 10 to 2,000 Hz (1% ∆RT, 1% ∆VR)
High Temperature Exposure 250 hours at 125°C (2% ∆RT, 2% ∆VR)
Rotational Life 200 cycles (3% ∆RT)
Load Life at 1.0 Watts 1,000 hours at 70°C (2% ∆RT)
Resistance to Solder Heat 260°C for 10 sec. (1% ∆RT)
MECHANICAL
Mechanical Stops Clutch Action, both ends
Torque, Starting Maximum 5oz.-in. (0.035 N-m)
Weight, Nominal .09 oz. (2.6 grams)
MODEL 78
1-1/4” Rectangular
Multiturn
Cermet Trimming
Potentiometer
Fluorinert® is a registered trademark of 3M Company.
Specifications subject to change without notice.
Model 78
1-62
Circuit Diagram
Marked On This Surface
Metal
Adjustment Screw
.110/2.794 ± 0.127 Dia. With .025/0.635
± 0.127 Wide X .031/0.787 ± 0.127 Deep Slot
0.07
1.78
Housing
Molded Plastic
.105
2.667
.32
8.13
.135
3.429
.30
7.62
.70
17.78
1.25
31.75
1.000 ± .005
25.400 ± 0.127
.125 ± .005
3.175 ± 0.127
.50 ± .03
12.70 ± 0.76
.195 ± .005
4.953 ± 0.127
3 Terminals Pins
Solderable
Dia.
.260 ± .015
6.604 ± 0.381
.015 ± .003
0.127 ± 0.076
.093 ± .005
2.362 ± 0.127 I.D.
2 Mounting Holes
Model No. &
Resistance
Value Marked
On This Surface
.10
2.54
.05
1.27
(1) (2) (3) .028 ± .003
0.711 ± 0.076
Model 78P
.062/1.575 Max.
Meniscus
3 Electrical Leads – 6/152 Min. Length
No. 30 AWG Teflon Insulated Stranded Wire
Yellow (1)
Red (2)
Green (3)
Model 78L
3 Terminals Pins
Solderable
Dia.
.30 ± .02
7.62 ± 0.51
.26 ± .02
6.60 ± 0.51
.70 ± .02
17.78 ± 0.51
.156 ± .031
3.962 ± 0.787
(3 Places)
.10 ± .02
2.54 ± 0.51
.05 ± .02
1.27 ± 0.51
.028 ± .003
0.711 ± 0.075
.187 ± .031
4.750 ± 0.787
(1)
Dia.
(2) (3)
Model 78S
SIDE ADJUSTMENT (Inch/mm)
Note: Model 78P dimensions applicable to all other models except as noted.
1
1-63 Model 78
(1) (2) (3) .344 ± .031
8.738 ± 0.787
.250 ± .015
6.350 ± 0.381
1.344
34.138
12-28 UNF-2A Thread
Max.
0.94
2.388 Max.
Model 78SBW (Adapter Pre-Assembled with Trimmer)
.250 ± .015
6.350 ± 0.381
1.344
34.138
12-28 UNF-2A Thread
Max.
0.94
2.388 Max.
Model 78LBW (Adapter Pre-Assembled with Trimmer)
.125 ± .005
3.175 ± 0.127
Metal Bushing Mount
Brass-Nickel Plated
Use .22/5.613 Dia. Min. Mounting Hole
Lock Washer, Panel Nut, Sealing Washer
& Mounting Screws Provided
Mounting Surface
Dia. Hole
1.56
3.962
.312 ± .015
7.925 ± 0.381
Max.
.437
11.100Max.
Model 56BW (Adapter Only)
PANEL MOUNT ADAPTER (Inch/mm)
1-64 Model 78
CIRCUIT DIAGRAM
(1)
(2)
(3)
CW
NOTES
mm
INCH
Metric equivalents, based on 1 inch = 25.4mm are
rounded to the same number of significant figures
as in the original English units and are provided for
general information only.
Tolerances unless otherwise specified:
Linear = ± .01 inches (.25mm)
Angular = ± 2 degrees
ORDERING INFORMATION
78 P BW R 10K LF
Model Series
Pin Style
RoHS Compliant Code - optional
Resistance Value
Resistance Prefix
Optional Panel
Mount Adapter
Note: Use ‘56BW’ to order panel mount adapter without trimmer
PACKAGING
Standard: Boxes
Capacity = 25 Units
STANDARD RESISTANCE VALUES, OHMS
10 200 5K 50K 500K
20 500 10K 100K 1Meg
50 1K 20K 200K 2Meg
100 2K 25K 250K
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
TT Electronics:
78LBWR2KLF 78LR100LF 78LR100KLF 78LR1KLF 78LR500KLF 78PBWR2KLF 78PBWR50LF 78PR10LF
78PR100KLF 78PR1KLF 78PR200LF 78PR200KLF 78PR25KLF 78PR2KLF 78PR500LF 78PR500KLF
78SBWR50KLF 78PR6.5MEG 78PR1MEG 78LBWR10K 78LR2KLF 78LR200LF 78LR2MEGLF 78PR25K
78LBWR20LF 78LBWR250KLF 78PR2MEGLF 78LBWR1KLF 78LBWR200LF 78PBWR100KLF 78PBWR10KLF
78PBWR1MEGLF 78PBWR20LF 78PBWR2MEGLF 78PBWR500LF 78PR1MEGLF 78PR20LF 78PR50LF
78LBWR10LF 78LR20KLF 78PBWR100LF 78LR50KLF 78PBWR10LF 78PBWR1KLF 78PBWR250KLF
78PBWR5KLF 78PR100LF 78LBWR50LF 78LBWR500LF 78LBWR500KLF 78LR250KLF 78LR25KLF 78LR500LF
78PBWR20KLF 78PBWR500KLF 78PBWR50KLF 78PR250KLF 78LBWR100KLF 78LBWR200KLF 78LR1MEGLF
78LR20LF 78LR50LF 78LR5KLF 78PBWR200LF 78PBWR200KLF 78PBWR25KLF 78LBWR100LF
78LBWR10KLF 78LBWR1MEGLF 78LBWR25KLF 78LR10LF 78LBWR2MEGLF 78LBWR50KLF 78LBWR20KLF
78LBWR5KLF 78LR10KLF 78LR200KLF 78SBWR100LF 78SR50LF 78SR25KLF 78SBWR100KLF 78SBWR20LF
78SR100LF 78SBWR50LF 78SBWR5KLF 78SBWR2KLF 78SR100KLF 78SBWR20KLF 78SBWR500LF
78SR500KLF 78SBWR1KLF 78SBWR200LF 78SR1MEGLF 78SBWR200KLF 78SR10LF 78SR250KLF
78SBWR250KLF 78SR2MEGLF 78SR10KLF 78SBWR500KLF
