Categories
Statistics
Flag Counter
Since 08.08.2014
Counts only, if "DNT = disabled".

Your IP is 3.233.232.160
ec2-3-233-232-160.compute-1.
Info
Valid HTML 4.01 Transitional Creative Commons Lizenzvertrag
rss
เราจะทำแบบวิศวกรผู้ยิ่งใหญ่
We love the King
25. July 2024
ERRATA
C8 (1µF) is on the schematics but not on the layout. Please add above the 7812.
Your valuable opinion :
5 stars

Avg. 5.32 from 84 votes.



Curve_Tracer_advanced.php    8553 Bytes    18-06-2024 22:27:32


Curve Tracer Project .:. Part 2


A slightly more advanced version ...




Homebrew Curve Tracer



This is the advanced version of the simple Curve Tracer. It offers a current limiter, and a base/gate Driving Section.


Circuit Description




current limiter



The design is straightforward, the main focus was on easy design. Of course, an LM-10 would have a lower voltage drop, but the cost is 10 times higher :-( It follows a relais to switch the polarity. (NPN or PNP). This voltage is then applied to the collector or drain of the transistor. This voltages also is the [HORIZONTAL DEFL.] A shunt (R23,10Ω) in connection with an 10x amplifier (IC2a) amplifies the voltage drop at the shunt to give a 100mV / 1mA reading. [VERTICAL DEFL.] The 3rd transformer is used to generate an impulse to trigger the counter (74HC191) which counts from 0 to 7.


Impulsformer Counter with R2R Network


The output of this counter forms with an R2R-network a staircase which is amplified to 7 Vpp. (adjusted with R20). This staircase is inverted with IC6a and another relais switches between the polarity (NPN or PNP). In case a fet is to be analysed, a switch selects between 0.5 V/DIV and 1.0 V/DIV. In case a bipolar transitor is to be analysed, a voltage controlled current source generates the drive current. This is done by IC6c,d. The 3rd transformer also generates the supply voltages of -12V, +5V, +12V.


Measurement / Handling




The handling is almost self explanatory. In this section we will show some measurents and how to obtain them.


[LEFT] BY 228 Diode   [RIGHT] Resistor

BY228 Resistor


[LEFT] Varistor EPCOS S20K30    [RIGHT] Capacitor 100µF

S20K30 ELKO


[LEFT] Transformer, primary    [RIGHT] BC141-16, Base Drive : 10µA, 40V, 5mA

Trafo BC141-16





FAQ




I get a lot of emails concerning R8.

R8 is used to define the current for BJT's. IC4 together with the R2R Network produce a staircase waveform. With R10 this can be adjusted to 1V/step.

IC6d and IC6c generate a current. (I=U/R)

You can use any switch you have. I used one with seven positions to generate a Base Drive of 10-20-50-100-200-500-1000 microAmp /DIV

Therefore I used the following Resistors: 100kR-50kR-20kR-10kR-5kR-2kR-1kR

Schalter Schalter




✈ Downloads








✈ Share your thoughts



The webmaster does not read these comments regularely. Urgent questions should be send via email. Ads or links to completely uncorrelated things will be removed.


Your Browser says that you allow tracking. Mayst we suggest that you check that DNT thing ?

 
t1 = 6587 d

t2 = 169 ms

★ ★ ★  Copyright © 2006 - 2024 by changpuak.ch  ★ ★ ★

Impressum