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exp02-series-regulator

Generated 2026-08-25 · evaluated by ltspice · manifest version 1

The question, verbatim

Calculate the output voltage in both load and line regulation and Zener diode current in the regulator circuit shown below using LTspice.
extractor
human transcription from screenshot
file
lab manual, section 2.14 open ended question (screenshot, circuit diagram in image)

What it asks for:

Results

measurementvaluerunhowstanding
vout_nominal7.48403263092041nominalsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
vb_nominal8.292138713092461nominalsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
iz_nominal-0.0036895410157740116nominalsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
vout_low7.46865177154541linesweepsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
at V1 = 12
vout_high7.498468399047852linesweepsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
at V1 = 20
line_reg_pct0.39922369410820396derived / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
100 * (vout_high - vout_low) / vout_low
12 V to 20 V input, normalised to the 12 V output
vout_noload7.585122108459473loadsweepsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
at RL = 100k
vout_fullload7.447519779205322loadsweepsimulation / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
at RL = 500
load_reg_pct1.8476262344191192derived / ltspiceEXTERNAL an outside tool computed this, so a bug of ours shows up as disagreement
100 * (vout_noload - vout_fullload) / vout_fullload
no-load to full-load, normalised to full-load

Regime checks

assertionrunverdictwhat it examined
zener_in_breakdownnominal / D1heldI(D1) against a 0.0001 A minimum reverse current, and its terminal voltage against Vz=8.3 V, at 1 operating point of run 'nominal'
bjt_activenominal / Q1heldVce of Q1 against 0.2 V, and Ib for cut-off, at 1 operating point of run 'nominal'
zener_in_breakdownlinesweep / D1heldI(D1) against a 0.0001 A minimum reverse current, and its terminal voltage against Vz=8.3 V, at 9 sweep points of run 'linesweep'
bjt_activelinesweep / Q1heldVce of Q1 against 0.2 V, and Ib for cut-off, at 9 sweep points of run 'linesweep'
zener_in_breakdownloadsweep / D1heldI(D1) against a 0.0001 A minimum reverse current, and its terminal voltage against Vz=8.3 V, at 5 sweep points of run 'loadsweep'
bjt_activeloadsweep / Q1heldVce of Q1 against 0.2 V, and Ib for cut-off, at 5 sweep points of run 'loadsweep'

Checks that did not run

Every check this target defines ran: no checks were skipped. Stated positively rather than left blank, because an empty section reads the same as an unexamined one.

Download

The layout in these files is generated mechanically — a grid for LTspice, columns by logic depth for Logisim. It is correct, not pretty, and it will not resemble a hand-drawn schematic.

Devices and design choices

refpartpolicymodel cardwhy
D1DZ8V3synthesized.model DZ8V3 D(BV=8.3 IBV=5m)using a synthesised model: Vz=8.3 V anchored at a 5m test current, because the question specifies exactly 8.3 V and a nearby real part would answer a slightly different question
Q1QNPN_BF100synthesized.model QNPN_BF100 NPN(BF=100)using a synthesised NPN(BF=100) model, the parameters the question specifies

The record

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