Floating-Ground by SV1AFN

Motorola 2N5109 Amplifier Complete KIT EUR 18.89



Motorola 2N5109 Amplifier PCB only EUR 3.90

The prices do not include 24% Greek VAT applicable only to individual buyers from European Union. 

Fig. 2 - The schematic diagram.

Fig. 1 - An assembled  52x52 mm PCB Module.

A complete KIT of parts, connectors, as shown in the assembled PCB photo, including the gold-plated ENIG FR4 high-quality PCB is available.

The shipping is with registered mail with tracking (your signature is required on delivery) and is not included in the price. I usually ship the next day and it takes about a week to 10 days for USA or Australia, less than a week for Europe.


Download the schematic diagram


Download Building Instructions

A General Purpose 2N5109 Amplifier


Use it as a receive pre-amp, post mixer amp, ssb tx driver etc.


This is a well known transistor for many old hams. You can see it appearing in recent designs too. It is a nice transistor and you can build a nice linear amplifier with low noise figure (3...4 dB), high linearity, high dynamic range and much of stability.

My implementation is shown in the following schematic diagram. It is biased at 55mA and has a different feedback circuit. It's gain is around 14 dB, output attenuator loss included and it is broadband for more than 110 MHZ. Good for terminating a mixer's IF port.

It's output P1dB is +23dBm and this makes it suitable for driving a high-level mixer LO port as well.