#Transistor tester diagram install
#Transistor tester diagram mod
#Transistor tester diagram full

IC2: MCP1702 high precision voltage regulator instead of HT7550 low precision voltage regulator.

The concrete changes, referenced to the schematics:

1x Microchip MCP1702-5002E/TO - LDO Voltage Regulator 5V 250mA 0.1%.

3x TE Connectivity H8680RBYA - Metal Film Resistor 680R 0.1%.

3x TE Connectivity H8470KBZA - Metal Film Resistor 470K 0.1%.

Also added a 16MHz crystal for increased speed: I chose to order 0.1% resistors and just the MCP1702 voltage regulator, skipping the voltage reference.

#Transistor tester diagram mod

Therefore the k-firmware needs the resistor mod (step #3) to make it believe that there isn't any reference.' The k-firmware handles external references a little different and always checks for a 2.5V reference (no setting to disable that). When HW_REF25 is disabled (default setting) the firmware will ignore any external voltage reference. ' For running the m-firmware you can skip step #3 or remove R16 (no need to replace it). This post confirms that it's only necessary for the k-firmware: The part about R16 in the readme of the k-firmware is confusing since it's not mentioned in the readme of the m-firmware. If you're using a MCP1702 with a typical tolerance of 0.4% as voltage regulator you really don't need a 2.5V voltage reference.' Otherwise it would make the results worse. ' The external 2.5V voltage reference should be only enabled if it's at least 10 times more precise than the voltage regulator. This helps the software to detect the missing voltage reference.'

#Transistor tester diagram install

If you don’t install the precision voltage reference and you don’t add the relay extension, you should install a pull up resistor R16 to PC4 with a higher resistance value (47kΩ). ' The additional 2.5V precision voltage reference connected at pin PC4 (ADC4) can be used to check and calibrate the VCC voltage, but is not required.

#Transistor tester diagram full

Measurement type resistors (tolerance of 0.1%) to get the full accuracy.' ' The resistors R1 to R6 are critical for measurements and this 680Ω and 470kΩ resistors should be To improve the accuracy of the tester there are some simple modifications you can do.

Terminals for frequency generator, frequency counter and voltage reader.

5.5mm x 2.1mm center positive barrel jack for 9V.

I have the GM328 kit from Banggood ( no longer available there), sometimes identified as AY-AT. There are many different types, and they are usually very cheap. It not only reads transistors and tells you whether it's NPN or PNP, but it tells you the resistance of resistors or capacitance of capacitors, and more.

Documentation of my modifications to the AVR Transistortester.Ī transistor tester is a device where you can insert different kinds of electronic components and have them analyzed.