7CT1N: Difference between revisions

Revision as of 05:13, 5 December 2016

Template:Plugin Sidebar 2 The Tektronix 7CT1N is a curve tracer plug-in for 7000-series scopes. The 5CT1N plug-in for 5000-series scopes is very similar.

It can be installed in either a vertical or a horizontal compartment, a front-panel switch must be set accordingly. A pull-out cable with a plastic BNC plug connects to the input of a module installed in the corresponding plugin for the other axis, with a fixed 100 mV/Div scaling compatible with time base X inputs.

Internally, a variable-amplitude 55 Hz triangle-wave source supplies a transformer to step up the drive voltage and decouple it from ground (Emitter terminal). A step source supplies base current or gate voltage to the DUT. The amplifier for the current axis can be switched into a x1000 mode to detect leakage currents (of typical 1970s semiconductors, anyway).

Key Specifications

DUT drive voltage (C-E)	positive (NPN or N channel) or negative (PNP or P channel) half-waves 7.5 V, 0.5 V/Div, 240 mA peak 30 V, 2 V/Div, 60 mA peak 75 V, 5 V/Div, 24 mA peak 300 V, 20 V/Div, 6 mA peak HV warning light on for > 50 V peak power 500 mW
DUT current display	10 μA/Div to 20 mA/Div, 1-2-5 steps (x 1 mode) 10 nA/Div to 20 μA/Div, 1-2-5 steps (x 1000 mode)
Base/Gate drive	0 to at least 10 steps dual polarity variable offset, at least +/- 5 steps current mode: 1 μA/Step to 1 mA/Step in 1-2-5 sequence voltage mode: 1 mV/Div to 1 V/Div in 1-2-5 sequence, 1 kΩ current limit
DUT connection	Three 4 mm jacks / binding posts
DUT adapters	013-0072-00 Axial diodes 013-0069-00 Devices with long leads 013-0070-01 Transistors in TO-3 or TO-66 cases 013-0074-00 Transistors with stud leads 013-0110-00 Diodes with stud leads 013-0112-00 Transistors in TO-36 cases 013-0128-00 Transistors in TO-5 or TO-18

Links

Common Problems

C30 and C32 (100 μF, 25 V) are under-rated and therefore have a tendency to leak or short, causing associated resistors R30 and R32 (240 Ω, 0.25W, 5%) to overheat and fail. C30 and C32 should be replaced with modern equivalents rated at 63 V.

Prices

Year	Price	2015 value
1971	$400	$2,320
1980	$1,000	$2,870
1990	$2,100	$3,790

Pictures

7CT1N front
7CT1N left side
7CT1N right side
7CT1N tracing a BC337

@@ Line 11: / Line 11: @@
 * [http://w140.com/smb/7ct1n_sm.pdf Tektronix 7CT1N Manual (OCR, PDF)]
 }}
-The '''Tektronix 7CT1N''' is a [[curve tracer]] plug-in for [[7000-series scopes]].
+The '''Tektronix 7CT1N''' is a [[curve tracer]] plug-in for [[7000-series scopes]].  The [[5CT1N]] plug-in for [[5000-series scopes]] is very similar.
 It can be installed in either a vertical or a horizontal compartment, a front-panel switch must be set accordingly.
 A pull-out cable with a plastic BNC plug connects to the input of a module installed in the corresponding
@@ Line 61: / Line 62: @@
 ==Common Problems==
-C30 and C32 (100 μF, 25 V) have a tendency to leak or short,
+C30 and C32 (100 μF, 25 V) [http://hakanh.com/dl/docs/hardtofind/CT1N.pdf are under-rated] and therefore have a tendency to leak or short,
-causing associated resistors R30 and R32 (240 Ω, .25W, 5%) to overheat and fail.
+causing associated resistors R30 and R32 (240 Ω, 0.25W, 5%) to overheat and fail. C30 and C32 should be replaced with modern equivalents rated at 63 V.
-A good preventive maintenance procedure would be to
-replace these two capacitors with modern equivalents.
-Three 7CT1N units purchased online had this fault,
-and replacement of the capacitors and resistors restored proper operation.
 ==Prices==
@@ Line 93: / Line 89: @@
 <gallery>
-File:tek-7ct1n-front.jpg | 7CT1N front
+tek-7ct1n-front.jpg | 7CT1N front
-File:tek-7ct1n-left.jpg  | 7CT1N left side
+tek-7ct1n-left.jpg  | 7CT1N left side
-File:tek-7ct1n-right.jpg | 7CT1N right side
+tek-7ct1n-right.jpg | 7CT1N right side
-File:7ct1n-bc337.jpg     | 7CT1N tracing a BC337
+ct1n-bc337.jpg     | 7CT1N tracing a BC337
 </gallery>