®
P R E C I S I O N B U L K M E T A L
F O I L T E C H N O L O G Y
VIS HAY 12 8 0 AND 12 8 5 G S ERIES
Pre c is ion Trim m ing Pote ntiom e te rs
3/4" Re c tiline a r, ±5 ppm /°C a nd ±15 ppm /°C TCR
FEATURES
• Temperature Coefficient of Resistance (TCR):
<15 ppm/°C (Model 1280G); <5 ppm/°C (Model 1285G)4
(–55°C to +125°C Ref. @ +25°C); through the wiper
±50 ppm/°C
• Load Life Stability: 0.5% Maximum ∆R under Full Rated
Power @ +25°C for 2,000 hours
• Settability: 0.05% Typical; 0.1% Maximum
• Setting Stability: 0.1% Typical; 0.5% Maximum, ∆SS
• Power Rating: 0.75 watts @ +25°C
• Resistance Range: 10 Ω to 20K Ω
• Resistance Tolerance: ±10%, ±5 %
• Backlash: < 0.05%
• Tap Test: 0.05% Typical; 0.1% Maximum
TABLE 1 - 1 2 8 0 G AND 1 2 8 5 G S ERIES
TABLE 2 - 1 2 8 0 G AND 1 2 8 5 G S ERIES
MECHANICAL SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
Adjustment Turns
Backlash
Stops
26 ±2 turns
Resistance Tolerance
Model 1280G 10%1
Model 1285G 5%
<0.05%
Resistance Range
10 Ω to 20K Ω
clutch, wiper idles
+85°C water immersion
5 oz. in. Max.
T.C.R. Model 1280G
+15 ppm/°C (–55°C to +25°C)
–15 ppm/°C (+25°C to +125°C)
Sealed
Torque
T.C.R. Model 1285G 4
Power
+5 ppm/°C (–55°C to +25°C)
–5 ppm/°C (+25°C to +125°C)
Weight
1.5 grams Max.
0.75 W @ +25°C derated linearly
to zero watts @ +125°C (See Fig, 2)
Construction
Case Material
Lead Screw
Wiper
Valox®
Brass
Settability
0.05% Typical2; 0.1% Maximum
Precious Metal Brush
Nylon
Rider Block
Element
Lead Material
Setting Stability
0.1% Typical; 0.5% Maximum,
∆SS
Bulk Metal® Foil
Gold Plated Phosphor Bronze
Roll-on, Roll-off
0.25% Typical; 1.0% Maximum
Load-Life Stability
0.5% ∆R after 2,000 hours under
Full Rated Power @ +25°C
TABLE 3 - S TANDARD VALUES
End Resistance
C.R.V.3
2 Ω Maximum
3 Ω Typical; 10 Ω Maximum
10 Ω, 20 Ω, 50 Ω, 100 Ω, 200 Ω, 500 Ω
1K, 2K, 5K, 10K, 20K
Frequency Characteristics 10 ns rise time @ 1K Ω to 100 MHz
NOTES
HOW TO ORDER 1 2 8 0 /1 2 8 5 S ERIES P ARTS :
1. 5% Available on Special Order.
Please specify Vishay Model 1202 Precision Trimming Potentiometers
as follows:
2. Typical is a designer’s reference which represents that 85% of the
units supplied over a long period of time, will be at least the figure
shown or better.
Example:
10%
1280G
100R
3. The 1280G can be screened for low noise, if required.
4. For model 1285G 10 Ω and 20 Ω TCR is ±10 ppm/°C
5. Panel mount available on special order.
Model No.
Resistance Value Tolerance
VISHAY FOIL RESISTORS, 63 Lincoln Highway, P.O. Box 4004, Malvern, PA 19355-0988 • Phone (610) 644-1300
App. Eng. Phone (610) 251-5289 • App. Eng, Fax (610) 640-4487 • Sales Phone (610) 251-5842 • Sales Fax (610) 640-9081
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