10 Watt Linier Amplifier

10 Watt Linier Amplifier Circuit Diagram

It is absolutely accessible to get a watt or added with actual simple equipment, but to get added than 5 watts becomes a little added difficult. This commodity describes a 10 watt beeline amplifier that is able of carrying over 15 watts into 50 ohms and uses bargain artificial transistors that are acclimated in CB equipment. If you accept adversity in award 2SC2078 again lift the lid of your CB set to acquisition a acceptable alternative. The bent architect transistor, TR4, is apparent TIP31 in the ambit diagram, but actuality you can use aloof about annihilation that will fit. You could alike use addition 2SC2078, if you had money to burn, but added applied apparatus would be TIP41, TIP3055, MJE3055. All that affairs is that it will canyon up to 1 Ampere and accept the actual abject capacity in a TO220 case.

The amplifier has a advanced bandwidth, from 1.8 MHz through to over 30 MHz. The drive akin appropriate is alone about 2 - 5 mW beneath 14 MHz, ascent to 10 mW at 30 MHz. You can accordingly accomplish a acceptable QRP CW rig with annihilation added than this PA and a simple clear oscillator. I can accomplish 12 watts out of abundance application a 10-turn bend about my Grid Dip Oscillator! I can get over 15 watts from my Marconi arresting generator, but aloft about 12 watts it is actuality over-driven an may not be actual nice to attending at on the spectrum analyser. The ambit was advised to be as apple-pie as possible.

The circuit was originally advised to accompany my phasing-type SSB exciter, but it can be acclimated to amplify about any HF arresting from 2mW in the HF band. Note that there is bare a Low-Pass clarify amid the amplifier and antenna. This is a claim for ALL transmitters.

L1 matches a 50-Ohm ascribe to the 10-Ohm ascribe impedance of TR1. The achievement of TR1 is accompanying via T1 to TR2 and TR3 bases. T1 additionally transforms the impedance to the actual low ascribe impedance of these two transistors, so the accessory ambagious charge be absolutely blubbery wire.

TR2 and TR3 amplify the arresting alike further, up to about 12-Watts. They are in a push-pull agreement so T1 accessory and T2 primary charge both be symetrical. T2 increases the achievement impedance to 50-Ohms.

TR1, TR2 and TR3 all accept a 330R and 10n amid the beneficiary and abject terminals. This is bare for adherence and is a awkward anatomy of neutralising. Without these apparatus again the stages would about absolutely oscillate or accomplish affected signals. An added 180pf capacitor from both TR2 and TR3 collectors to arena (not apparent in the ambit diagram) accord the amplifier an alike cleaner achievement signal. The 68pf capacitor beyond the achievement may be added if you never use the 30MHz band. It, too, increases the adherence and helps to accumulate the harmonic agreeable low. My spectrum analyser did not appearance any cogent affected or harmonic outputs from 0 - 100MHz back apprenticed at 10-watts continuous, 14MHz. All affected outputs were bigger than -60dBm (-70dBc), which I admitting was appealing good!

TR4 is annihilation added than a high-current connected voltage alternation regulator application a 3v3 Zener diode for stability. It provides the base-bias voltage for TR2 and TR3. The 1K thermistor is thermally accompanying to the tinned-copper heatsink to abate the bent a little back the PA gets hot. Added about the thermistor later.