Learning Objectives
By the end of this lab, you will be able to:
- Construct half-wave, full-wave center-tapped, and full-bridge rectifier circuits on a virtual breadboard in Tinkercad Circuits, using a function generator as the AC source and an oscilloscope to observe waveforms.
- Trace the conduction path through each circuit during the positive and negative half-cycles, identifying which diode(s) conduct and which block on every half-cycle.
- Measure the input and output peak voltages of each rectifier and account for the difference using diode drops β one 0.7 V drop for half-wave and center-tapped, two drops (β1.4 V) for the bridge.
- Compare the output ripple frequency of half-wave (equal to the line frequency) against full-wave circuits (double the line frequency), and explain why this makes full-wave rectifiers easier to filter.
- Calculate the average (DC) value of each rectified waveform β VDC β 0.318 Vp for half-wave and β 0.637 Vp for full-wave β and verify against simulation.
- Demonstrate capacitive filtering by adding a reservoir capacitor across the load and relating ripple amplitude to capacitor size and load resistance.
- Evaluate the three topologies against each other β component count, output voltage, PIV stress, transformer requirements, and efficiency β and select the appropriate rectifier for a given application.
Key Terms & Concepts
Click any card to reveal its definition. Review these before you build.
Rectification Basics
Rectifier
Rectification Basics
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Definition
A diode circuit that converts AC into pulsating DC by allowing current through the load in only one direction. The first stage of nearly every power supply β the diode lab's "one-way valve" put to work.Half-Wave Rectifier
Rectification Basics
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Definition
One diode in series with the load: passes the positive half-cycles, blocks the negative ones. Simple and cheap, but half the input energy is thrown away and the output ripples at the line frequency.Full-Wave Rectifier (CT)
Rectification Basics
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Definition
Two diodes fed by a center-tapped transformer secondary. Each diode handles one half-cycle, steering both halves through the load in the same direction β but each half only sees half the secondary voltage.Full-Bridge Rectifier
Rectification Basics
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Definition
Four diodes in a diamond: diagonal pairs conduct on alternate half-cycles, rectifying the full source voltage with no center tap needed. The dominant topology in real power supplies β at the cost of two diode drops (β1.4 V).Waveform Measures
Pulsating DC
Waveform Measures
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Definition
Rectifier output before filtering: current always flows the same direction (DC), but the magnitude pulses between zero and the peak. Useful for charging batteries; too bumpy for electronics until filtered.Ripple Frequency
Waveform Measures
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Definition
How many output pulses occur per second. Half-wave: one pulse per input cycle (60 Hz in β 60 Hz ripple). Full-wave and bridge: two pulses per cycle (60 Hz in β 120 Hz ripple) β the fingerprint that tells you which rectifier you're looking at on a scope.Average (DC) Value
Waveform Measures
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Definition
What a DC voltmeter reads across the load: the area under the waveform averaged over a cycle. Half-wave: VDC = Vp/Ο β 0.318 Vp. Full-wave: VDC = 2Vp/Ο β 0.637 Vp β double, because no half-cycle is wasted.Peak Inverse Voltage (PIV)
Waveform Measures
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Definition
The maximum reverse voltage a diode must survive while blocking. Half-wave: PIV = Vp. Center-tapped: PIV = 2Vp (the whole secondary lands on the off diode). Bridge: PIV β Vp β a hidden advantage of the four-diode design.Filtering & Sources
Filter (Reservoir) Capacitor
Filtering & Sources
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Definition
A large capacitor across the load that charges to the peak and supplies the load between pulses, smoothing pulsating DC toward steady DC. Bigger C (or lighter load) β slower discharge β less ripple.Ripple Voltage (Vr)
Filtering & Sources
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Definition
The small peak-to-peak sawtooth left on a filtered output as the capacitor discharges between peaks. Approximated by Vr β Iload / (fripple Β· C) β which is why 120 Hz full-wave ripple filters twice as well as 60 Hz half-wave ripple with the same capacitor.Function Generator
Filtering & Sources
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Definition
Tinkercad's adjustable AC source: choose sine wave, set frequency and amplitude. It stands in for the wall-transformer secondary in this lab, since Tinkercad Circuits has no transformer component.Oscilloscope
Filtering & Sources
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Definition
Draws voltage versus time. In Tinkercad each scope is single-channel: use one across the source and one across the load to compare input and output simultaneously. Set the time-per-division so 2β3 full cycles fit on screen.π₯ Tinkercad Setup Notes for AC Circuits
You already know the Tinkercad basics from the Basic Diode lab (parts panel, R to rotate, inspector to set values, Start Simulation). Rectifier work adds two instruments and one important limitation:
- Function Generator (search "function generator"): set Function = Sine, Frequency = 60 Hz. Set the amplitude, then verify the actual peak on the oscilloscope β checking whether an instrument's "amplitude" field means peak or peak-to-peak is a professional habit, and the scope is the referee. Adjust until the scope shows Β±10 V peaks.
- Oscilloscope (search "oscilloscope"): two terminals, wired in parallel like a voltmeter. Set Time Per Division β 5 ms so about three 60 Hz cycles fill the screen. Use two scopes β one on the source, one on the load β to compare input and output side by side.
- No transformer exists in Tinkercad. For the center-tapped circuit you will emulate the secondary winding with two identical function generators in series, grounding the midpoint: the junction behaves exactly like a center tap, with the two outer ends swinging equally above and below it. This is a standard simulator workaround β and wiring it forces you to understand what a center tap actually is.
Keep the Two Generators Identical
In Part 2, both function generators must have the same waveform, frequency, and amplitude settings, wired + to β in series (head to tail). If one is flipped or mismatched, the two half-cycles of your output will be unequal β which is itself a useful diagnostic to observe once, on purpose.
π§ Virtual Parts List
| Qty | Component (Tinkercad name) | Setting | Used In |
|---|---|---|---|
| 1 | Breadboard (small) | β | All parts |
| 2 | Function Generator | Sine Β· 60 Hz Β· Β±10 V peak | 1 for Parts 1 & 3 Β· 2 for Part 2 |
| 2 | Oscilloscope | 5 ms/div | Input + output, all parts |
| 6 | Diode 1N4001 | β | 1 (half-wave) Β· 2 (CT) Β· 4 (bridge) |
| 1 | Resistor | 1 kΞ© | Load RL, all parts |
| 1 | Polarized Capacitor | 47 Β΅F β 470 Β΅F | Part 4 filtering |
| 1 | Multimeter | V (DC) | Part 4 average/DC readings |
| ~14 | Wires | red / black / green | All parts |
π The Three Circuits You Will Build
All three rectifiers drive the same 1 kΞ© load; only the diode arrangement changes. Study each schematic and its output waveform before building β your job in the procedure is to make Tinkercad's oscilloscope reproduce these green traces.
Figure 1 β Half-wave rectifier. One diode, one conduction path. Expected: Vp(out) β 9.3 V, ripple frequency 60 Hz, VDC β 0.318 Γ 9.3 β 3.0 V. PIV on D1 = full 10 V peak.
Figure 2 β Full-wave center-tapped rectifier (transformer emulated). Gens A and B in series, midpoint grounded β the junction is the "center tap." When the top end swings positive D1 conducts; when the bottom end swings positive D2 conducts. Both routes push current through RL in the same direction. Expected: Vp(out) β 9.3 V (one diode drop), ripple 120 Hz, VDC β 5.9 V. PIV on each diode = 2 Γ Vp = 20 V.
Figure 3 β Full-bridge rectifier. AC enters at the top and bottom nodes; DC exits at the left (β) and right (+) nodes. Positive half-cycle: current flows through D4 β RL β D3. Negative half-cycle: through D2 β RL β D1. Two diodes always in series with the load, so expected Vp(out) β 10 β 1.4 = 8.6 V, ripple 120 Hz, VDC β 5.5 V. PIV per diode β Vp only.
Expected Results at a Glance
| Circuit | Diodes | V_p(out) @ Β±10 V in | Ripple freq | V_DC (unfiltered) | PIV per diode |
|---|---|---|---|---|---|
| Half-wave | 1 | β 9.3 V | 60 Hz | β 3.0 V | V_p = 10 V |
| Full-wave CT | 2 | β 9.3 V | 120 Hz | β 5.9 V | 2Β·V_p = 20 V |
| Full-bridge | 4 | β 8.6 V | 120 Hz | β 5.5 V | β V_p = 10 V |
V_DC(half-wave) = V_p(out) / Ο β 0.318 Β· V_p(out) V_DC(full-wave) = 2 Β· V_p(out) / Ο β 0.637 Β· V_p(out) V_r(filtered) β I_load / (f_ripple Β· C)
π Step-by-Step Procedure
Part 1 β Half-Wave Rectifier (β20 min)
- Create the workspace. New circuit, renamed "LastName β Rectifier Lab." Place a small breadboard.
- Set up the AC source. Place a Function Generator left of the breadboard: Sine, 60 Hz. Wire its output terminals to two free breadboard columns (call them the source rails). Attach oscilloscope #1 across the generator, 5 ms/div.
- Calibrate the amplitude. Start the simulation and adjust the generator amplitude until scope #1 shows peaks of Β±10 V. Record the amplitude setting that achieves this β you'll reuse it all lab. Stop the simulation.
- Build the rectifier. D1 (1N4001) from the generator's top terminal, cathode band pointing toward the load, then RL = 1 kΞ© from D1's cathode back to the generator's other terminal β the series loop of Figure 1.
- Attach scope #2 across RL (same 5 ms/div) and run the simulation.
- Observe and record. Sketch or screenshot both traces. In Data Table 1 record Vp(in), Vp(out), the number of output pulses per input cycle, and the ripple frequency. Confirm Vp(in) β Vp(out) β 0.7 V.
- Flip test. Rotate D1 180Β° and re-run. The output pulses should now be negative humps β the diode passes the other half-cycle. Note this in your report, then flip D1 back.
Part 2 β Full-Wave Center-Tapped (β25 min)
- Emulate the center-tapped secondary. Add a second Function Generator directly below the first with identical settings (sine, 60 Hz, same amplitude). Wire Gen A's β terminal to Gen B's + terminal. That junction is your center tap (CT) β wire it to a breadboard rail and treat it as the 0 V reference.
- Verify the emulation. Run the simulation with scope #1 from Gen A's + end to CT, then move it to measure Gen B's β end to CT. Both should show Β±10 V sines β equal and opposite swings around the tap. Stop.
- Place the steering diodes. D1 from Gen A's outer (+) end, D2 from Gen B's outer (β) end β both cathode bands pointing toward a shared column, exactly as in Figure 2. Join both cathodes at that column.
- Connect the load. RL = 1 kΞ© from the shared cathode column back to the CT rail. Scope #2 across RL.
- Run and record. The gaps from Part 1 are now filled β every half-cycle produces a hump. Record Vp(out), pulses per input cycle, and ripple frequency (should be 120 Hz) in Data Table 1.
- Half-cycle detective work. Temporarily delete D2 and re-run: you're back to half-wave. Restore D2. One sentence for your report: what does each diode contribute?
Part 3 β Full-Bridge Rectifier (β25 min)
- Simplify the source. Delete Gen B and the CT wiring β the bridge needs only one generator, same Β±10 V sine.
- Build the diamond. Place four 1N4001s as in Figure 3. Breadboard tip: give each of the four bridge nodes its own 5-hole column group and label them mentally β AC-top, AC-bottom, DC+, DCβ. Both cathodes of D4 and D2 meet at DC+; both anodes of D1 and D3 meet at DCβ.
- Connect source and load. Generator terminals to AC-top and AC-bottom. RL between DC+ and DCβ. Scope #2 across RL with its + lead on DC+.
- Run and record. Full-wave humps again at 120 Hz β but measure Vp(out) carefully. It should be about 1.4 V below the input peak. In Data Table 1, record the values and identify which two diodes conduct on each half-cycle by tracing Figure 3.
- Fault insertion. Delete any ONE bridge diode and re-run. Predict first, then observe: the bridge degrades to a half-wave rectifier. Restore the diode. This is exactly how a real bridge with one failed-open diode behaves β a classic troubleshooting scenario.
Part 4 β Filter Capacitor & Ripple (β20 min)
- Add the reservoir. Keep the bridge circuit. Place a polarized capacitor across RL β stripe/β terminal to DCβ. Start with 47 Β΅F.
- Observe smoothing. Run the simulation. The humps become a DC level with a sawtooth ripple riding on top. Measure the ripple peak-to-peak on scope #2 and the DC level with the multimeter (DC V mode across RL). Record in Data Table 2.
- Scale the capacitor. Repeat with 470 Β΅F. Ripple should shrink roughly 10Γ, matching Vr β I/(fΒ·C).
- Ripple-frequency payoff. Move the 47 Β΅F capacitor to your Part 1 half-wave circuit and measure its ripple. Compare against the bridge with the same capacitor: the 60 Hz circuit ripples about twice as much β the practical reason power supplies use full-wave rectification. Record both in Data Table 2.
- Wrap up. Complete the Analysis Questions and Knowledge Check, then Print/Save your report with the data tables filled in.
Troubleshooting
Output looks identical to input? A diode is bypassed β check that the load current has no path around it. CT output has unequal humps? The two generators are mismatched or one is reversed. Bridge output is zero? Almost always one diode reversed in the diamond β hover each 1N4001 and confirm the anode/cathode labels against Figure 3. Filtered output at nearly 0 V with huge current? The polarized capacitor is in backwards.
π Data Tables
Type readings directly into the tables β they persist when you print this page.
Data Table 1 β Rectifier Comparison (unfiltered, Β±10 V / 60 Hz input)
| Circuit | V_p(in) | V_p(out) | Diode drop(s) = inβout | Pulses per input cycle | Ripple freq | Conducting diode(s), + half |
|---|---|---|---|---|---|---|
| Half-wave | ||||||
| Full-wave CT | ||||||
| Full-bridge |
Data Table 2 β Filtering & Ripple (1 kΞ© load)
| Circuit + Capacitor | V_DC (multimeter) | Ripple V_pp (scope) | Ripple freq | Observation |
|---|---|---|---|---|
| Bridge Β· 47 Β΅F | ||||
| Bridge Β· 470 Β΅F | ||||
| Half-wave Β· 47 Β΅F |
π Interactive Rectifier Waveform Explorer
This companion simulator models the same three circuits driving a 1 kΞ© load. The gray trace is the AC input; the green trace is what your Tinkercad oscilloscope should show across RL. Switch topologies, add a filter capacitor, and compare the readouts against your data tables.
What To Notice
Switch from Half-Wave to Bridge with the 47 Β΅F filter engaged and watch the ripple drop by roughly half without touching the capacitor β the 120 Hz pulses recharge the reservoir twice as often. Then compare CT versus Bridge peaks at the same input: the bridge loses an extra 0.7 V (two diodes in the path), the CT circuit only one β but remember the CT design pays for that elsewhere, in transformer cost and 2Vp PIV stress.
β Analysis Questions
Answer in complete sentences in your lab report.
- Using Data Table 1, compare the input-to-output peak difference for the half-wave and bridge circuits. Why is the bridge's difference approximately double?
- Both full-wave circuits produced 120 Hz ripple from a 60 Hz input. Explain, in terms of conduction paths, where the "extra" pulses come from.
- In Part 2, what physical transformer feature did the two series function generators emulate, and why did the midpoint have to be your 0 V reference?
- When you deleted one bridge diode in Part 3, the circuit became a half-wave rectifier. Trace and explain: which half-cycle was lost, and why did the other survive?
- Using Vr β I/(fΒ·C), predict the ripple for the bridge with 47 Β΅F (I β 8 mA, f = 120 Hz), and compare against your Data Table 2 measurement.
- The center-tapped design uses two fewer diodes than the bridge yet is rarer in modern supplies. Using your PIV column and the transformer requirement, argue why industry prefers the bridge.
- A car's alternator uses six diodes in a three-phase bridge. Based on this lab's pattern, predict the ripple frequency relative to the alternator's electrical frequency, and explain your reasoning.
Key Facts Reference Box
Half-wave ripple
f_in (60 Hz β 60 Hz)
Full-wave ripple
2 Γ f_in (60 Hz β 120 Hz)
Half-wave average
V_DC = V_p / Ο β 0.318 V_p
Full-wave average
V_DC = 2V_p / Ο β 0.637 V_p
Diode drops in path
HW: 1 Β· CT: 1 Β· Bridge: 2
PIV per diode
HW: V_p Β· CT: 2V_p Β· Bridge: βV_p
Filtered ripple estimate
V_r β I_load / (f_ripple Β· C)
Bridge conduction pairs
+half: D4+D3 Β· βhalf: D2+D1
Tinkercad transformer
None β emulate CT with 2 series gens
Reservoir capacitor
Bigger C β smaller ripple
Interactive Knowledge Check
Six questions drawn directly from the lab. Select an answer for each, then press Grade My Quiz.