Small-Signal ModelsLinearising a transistor around its bias point, and what transconductance actually is.Electrical EngineeringAround a bias point a nonlinear device behaveslinearly, described by its transconductance.BJT: g_m = I_C/V_T · FET: g_m = 2I_D/V_ovI_C = 1 mAg_m ≈ 38 mS1 mA ÷ 26 mV.β = 100r_π ≈ 2.6 kΩβ ÷ g_m.R_C = 1 kΩGain ≈ −38Bias sets gain.THE COMMON MISTAKEUsing the small-signal model for a large swingKeeping the signal well below the biasThe model is the first term of a Taylor expansion. Drive it hard and the terms youdropped return as distortion and clipping.To draw the small-signal circuit, kill the DC: supply rails become groundand bias current sources become open circuits.Small-Signal Modelslearnposters.com
Small-Signal Models — printable engineering wall chart from LearnPosters. Free vector PDF, US Letter and A4.

What’s on the Small-Signal Models poster

The rule, 3 worked examples, and the mistake everyone makes.

To draw the small-signal circuit, kill the DC: supply rails become ground and bias current sources become open circuits.

Questions about the Small-Signal Models poster

What’s on the Small-Signal Models poster?
The rule, 3 worked examples, and the mistake everyone makes. Around a bias point a nonlinear device behaves linearly, described by its transconduc…; BJT: g_m = I_C/V_T · FET: g_m = 2I_D/V_ov; I_C = 1 mA = g_m ≈ 38 mS; β = 100 = r_π ≈ 2.6 kΩ; R_C = 1 kΩ = Gain ≈ −38; Common mistake: Using the small-signal model for a large swing → Keeping the signal w…. To draw the small-signal circuit, kill the DC: supply rails become ground and bias current sources become open circuits.
Who is the Small-Signal Models poster for?
Small-Signal Models belongs to the Electrical Engineering section rather than to a school year, because engineering is not something one grade owns. Anyone learning electronics can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Small-Signal Models poster?
Use it to get gain out of a stage without solving the nonlinear device equations. A wall chart earns its place by being glanceable from where the work is happening, so Small-Signal Models belongs on the wall where that engineering work actually happens, within glancing distance, rather than filed away.
What other posters go with Small-Signal Models?
BJT Operating Regions, BJT vs MOSFET and Common-Emitter Amp sit alongside Small-Signal Models in the Electrical Engineering section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.BJT Operating RegionsBJT vs MOSFETCommon-Emitter Amp
Is the Small-Signal Models poster free to download and print?
Yes. Small-Signal Models downloads as a free PDF with no account, no email and no watermark, like everything else in the Electrical Engineering section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Small-Signal Models poster print at?
Small-Signal Models is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Small-Signal Models loses nothing.Printing guide

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