Amplifier NPN+PNP Transistors Tester Circuit

[lineup]

hi

Amplifer NPN+PNP Transistors Tester Circuit

When we build our transistor amplifiers, we very often want to use
Complementary NPN + PNP Transistor pairs.
As close matched as possible.

My circuit for this, you can see in Attachment.

A similar circuit should be possible to build.
This one I use for for testing my MultiSim spice models.
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About the schematic:
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This test shows BD139 / BD140 Testing.
I use 10 Volt C-E. But can be changed, of course.
Also the test CURRENT can be easily changed.
In this case I use 10mA for BD139/140.

- Q1 is transistor under test
- CCS 'I2' 2.11uA, is a compensation for base current in U2.
- CCS 'I3' is where I set test current
- V+ is 10.621V, as 0.621V is compensation for VBE of U2
- The negative PNP side is a mirror of NPN test side

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About my actual test result in the attached picture:
- VBE 0.667 and 0.653 Volt is alright
- Base currents: 77.7uA and 31.7uA is not alright

Because a gain difference hfe=128 and hfe=315 is too much.
So I should not use this pair for any Simulations!
I better try to find a some better matched BD139/BD140 spice models.


Finally .................................................. ....................
If you setup such a tester circuit, REAL or in your SIM, you may be very surprised!
Models of NPN+PNP that you have used may turn out to be less good .....
I really recommend you run this test, before you start designing Solid State Amplifiers.



Regards, lineup

[lineup]

And here is a useful
N-MOS + P-MOS Tester
To checkout that your Spice Models are somewhat correct.

My attachment Tester circuit
shows a test of IRF540N and IRF9540N.
At 1 Ampere and 10 Volt result is:
IRF540 VGS: +3.85V
IRF9540 VGS: -4.34V

Comparing this to figures in datasheet for these MOSFETs
shows that these both models are good!


Regards
lineup
Lineup Audio Lab