PC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteSome links on this page are affiliate links: if you buy through them we may earn a commission, at no extra cost to you.
This lab builds a non-inverting operational-amplifier circuit whose gain is adjusted with a potentiometer in the negative-feedback network. Connect the signal to the op amp’s non-inverting (+) input; the ideal closed-loop voltage gain is 1 + Rf/Rg. With equal feedback resistances, the expected gain is 2, provided the op amp stays within its linear operating limits.
What the experiment demonstrates
A non-inverting amplifier produces an output that changes in the same polarity as its input: when the input rises, the output rises, as long as the op amp is operating linearly. The input signal goes to the + input. A portion of the output is returned to the − input through a feedback network, and that network sets the closed-loop gain.
The input impedance is generally high compared with an inverting amplifier, but its actual value depends on the selected op amp and the surrounding circuit. The output is not unlimited: supply voltage, input range, load, and the op amp’s own operating limits constrain it.
The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →This is a practical version of the Analog IC Projects non-inverting amplifier lab. Its broader project-based context is described in the Analog Integrated Circuits chapter introduction.
#1 Best Overall
- Minidodoca high quality 24 Values 173 Pcs IC Assortment Kit
- IC chip Assortment contains: Op Amp: LM358 LM324 JRC4558 NE5532 LM386 TDA2030 TDA2822 UA741 ;Comparators: LM393 LM339;PhotoCoupler: PC817 ;Multivibrator: CD4047;Analog Multiplexer: CD4053;Echo Audio Processor: PT2399; PWM controller: UC3842 UC3843; Darlington Array ULN2003 ULN2803;Voltage Converter 7660; Timer: NE555
- Including 3 pcs DIP8 socket, 3 pcs DIP14 socket, 3 pcs DIP16 socket, 3 pcs DIP18 socket
- Including 1pc IC Plier included for easy picking and removing IC chips
- Minidodoca ic kit Complete specifications, clear markings, easily identifiable models, sufficient quantity, durable materials, nickel plated surface, not easy to rust, ensuring a long service life.
Parts and equipment
The referenced lab specifies one op amp, with 1458 or 353 devices recommended, three 6 V batteries or an 18 V supply, and two 10 kΩ linear-taper potentiometers. The 1458 and 353 are examples from that lab, not universal drop-in choices for modern circuits.
- Solderless breadboard and jumper wires.
- Digital multimeter for checking supply, input, and output voltages.
- Signal source, such as a function generator, for AC tests.
- Oscilloscope for inspecting AC gain, clipping, oscillation, and phase; it is optional for basic DC measurements.
- Supply bypass/decoupling capacitors placed close to the op amp’s supply pins, following the selected device’s datasheet and the circuit’s supply arrangement.
Before choosing a replacement op amp, check its datasheet for supply-voltage range, supported single- or split-supply operation, input common-mode range, output swing, package pinout, input offset, gain-bandwidth product, slew rate, output-current capability, and unity-gain stability. Never assume pin numbers or supply compatibility from another op amp model.
How the feedback sets gain
An idealized op amp follows Vout = A(V+ − V−), where A is its open-loop gain. With negative feedback and sufficient open-loop gain, the circuit drives the inverting input toward the non-inverting input, so V− ≈ V+. This approximate equality is sometimes called a virtual short; it is not a physical connection.
Rank #2
- 🔴 161 pcs 20 models, Each with individual compartment. Pin assignment table included.
- 🔴 IC Plier included for easy picking and removing IC
- 🔴 Op Amp: LM358 LM324 JRC4558 NE5532 LM386 TDA2030 TDA2822 UA741 Comparators: LM393 LM339
- 🔴 PhotoCoupler: PC817 Multivibrator: CD4047 Analog Multiplexer: CD4053 Echo Audio Processor: PT2399
- 🔴 PWM controller: UC3842 UC3843 Darlington Array ULN2003 ULN2803, Voltage Converter 7660 Timer: NE555
The feedback divider returns a fraction of the output to the − input. To make that feedback voltage match the input voltage, the op amp raises or lowers its output. For the conventional non-inverting arrangement, with Rf from output to the − input and Rg from the − input to the reference node:
Av = Vout/Vin = 1 + Rf/Rg
The approximation V− ≈ V+ and this gain formula describe linear closed-loop operation. They stop predicting the output correctly if feedback is lost, the op amp saturates, the signal exceeds the input common-mode range, or frequency and slew-rate limits become significant.
Wire the adjustable-gain circuit
Keep the roles of the two potentiometers distinct. The input potentiometer, R1, adjusts the signal voltage presented to the + input. The feedback potentiometer, R2, divides into two effective resistances and adjusts gain. In the feedback network, the upper effective resistance is Rf and the lower one is Rg.
Rank #3
- Comprehensive IC Kit: 20 different specifications with 180 pieces of IC integrated circuit combination set for various electronic projects and applications
- Diverse IC Components Included: The IC semiconductor chip combination includes operational amplifiers LM358, LM324, JRC4558, NE5532, LM386, TDA2030, TDA2822, UA741, comparators LM393, LM339, optocouplers PC817, multivibrators CD4047, analog multiplexers CD4053, echo sound processors PT2399, pulse width modulation controllers UC3842, UC3843, bipolar arrays ULN2003, ULN2803, voltage converters 7660, and timers NE555
- Complete Socket Set: Includes 6 DIP8 sockets, 6 DIP14 sockets, 6 DIP16 sockets, and 3 DIP18 sockets for easy installation and testing of integrated circuits
- IC Insertion Tool Included: Equipped with 1 IC insertion tool that facilitates convenient removal and installation of IC chips without damage to pins or components
- Quality Construction: This IC set features complete specification details, clear markings, easily identifiable model numbers, sufficient quantity, durable materials, and nickel-plated surfaces with resistance to rust for extended service life
- With power off, identify the chosen op amp’s supply and input pins from its datasheet. Do not transfer pin numbers from a different model or package.
- Connect the input signal, through the input adjustment arrangement, to the non-inverting (+) input.
- Connect the op amp output to one end of the feedback potentiometer.
- Connect the feedback potentiometer’s wiper to the inverting (−) input.
- Connect the other end of the feedback potentiometer to the circuit reference node, as in the lab’s schematic. The two sections between the ends and wiper form the feedback divider.
- Connect the supply pins using the polarity and supply arrangement allowed by the selected op amp. Check every supply connection before inserting or powering the IC.
- Connect the signal-source ground and measurement ground to the same circuit reference. Add supply decoupling close to the IC.
The original lab specifies three 6 V batteries or an 18 V supply, but that does not make 18 V safe for every replacement op amp. A circuit using a single positive supply may also need its signal biased around a suitable midpoint rather than centered on ground; a split-supply design can use a different reference arrangement. Follow the selected device’s datasheet and the actual schematic.
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesBuild and measure
- Start with a low input amplitude and the feedback control near its minimum-gain setting.
- Power the circuit and use a meter to verify the voltage at the op amp’s supply pins and the circuit reference.
- Set the feedback potentiometer near its midpoint. If its two effective sections are equal, the expected ideal gain is about 2.
- Measure the input and output for several input-potentiometer positions. Record values relative to the same reference.
- For each fixed feedback setting, calculate
Av,measured = Vout/Vin. The ratio should be approximately constant across input settings while the op amp remains linear. - Move the feedback potentiometer to another position and repeat the measurements. Then investigate the minimum and maximum settings, watching for a change in gain or clipping.
- Increase input amplitude or gain gradually, checking the output waveform with an oscilloscope for clipping, distortion, or oscillation.
For AC measurements, label all voltage values consistently as RMS, peak, or peak-to-peak. Do not divide an RMS output by a peak input, for example. For a DC test, record the actual DC input and output relative to the circuit reference.
| Feedback setting | Vin | Vout | Measured gain | Theoretical gain | Percent error |
|---|---|---|---|---|---|
| Minimum | Record measured value | Record measured value | Vout/Vin | 1 + Rf/Rg using measured or specified resistances | 100 × (measured − theoretical)/theoretical |
| Midpoint | Record measured value | Record measured value | Vout/Vin | 1 + Rf/Rg using measured or specified resistances | 100 × (measured − theoretical)/theoretical |
| Maximum | Record measured value | Record measured value | Vout/Vin | 1 + Rf/Rg using measured or specified resistances | 100 × (measured − theoretical)/theoretical |
Expected gain and potentiometer limits
Midpoint: approximately 2
When a 10 kΩ feedback potentiometer is modeled as two equal 5 kΩ sections, Av = 1 + 5 kΩ/5 kΩ = 2. In ideal linear operation, 0.1 V in gives 0.2 V out, 0.5 V in gives 1.0 V out, and 1.0 V in gives 2.0 V out. These are predictions, not guaranteed readings; the selected op amp and supply must support the input and output voltages.
Rank #4
- Wide Assortment of Operational Amplifiers
- Single and Dual Channel Selection
- Variety of Unique Sounding Op Amps
- Applicable to Numerous Applications
- Electronics Kit is Breadboard-Friendly and Protoboard Friendly
Minimum: unity gain in the ideal circuit
A conventional non-inverting amplifier has an ideal minimum gain of 1, or unity gain, when the feedback ratio approaches zero. The actual potentiometer arrangement may not reach exactly 1 because of wiper and end resistance, wiring resistance, tolerances, and the op amp’s limits. If the minimum setting makes the circuit a voltage follower, the selected op amp must be stable at unity gain.
Maximum: increasing gain can mean clipping
As the feedback network returns a smaller fraction of the output to the − input, theoretical gain rises. The maximum useful gain is constrained by output swing, supply voltage, input amplitude, open-loop gain, gain-bandwidth product, slew rate, load resistance, output-current capability, and potentiometer tolerance. If the requested output exceeds the op amp’s available swing, the waveform clips instead of following the gain formula.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Why measured results differ from the ideal
- Output swing and saturation: an op amp cannot generally drive its output all the way to both supply rails. The available range depends on the device and load. A clipped output no longer has the calculated gain.
- Input common-mode range: the voltage at the inputs must remain inside the device’s permitted range. This is especially important with single-supply operation.
- Bandwidth: a voltage-feedback op amp has finite gain-bandwidth product. Higher closed-loop gain generally leaves less bandwidth, so the DC gain formula alone does not predict high-frequency response.
- Slew rate: a large or fast-changing output may not be able to follow the requested waveform, causing distortion even before an obvious rail limit.
- Loading: a low-resistance load draws more output current and may reduce output swing. The source impedance and feedback network also affect behavior.
- Potentiometer accuracy: mechanical midpoint is not guaranteed to be electrical midpoint, and wiper resistance or intermittency can shift the ratio.
- Offset, bias current, and resistor choice: real op amps have input offset and bias currents. Very large resistors can increase noise and bias-current errors; very small values increase loading and feedback current.
- Frequency and layout: parasitic capacitance, long breadboard wires, grounding, and load interaction can alter frequency response or stability.
Troubleshooting symptoms
| Symptom | Likely causes | Checks and corrective action |
|---|---|---|
| Output stuck near a supply rail | Open feedback path; inputs reversed; wrong supply pin or polarity; input outside common-mode range; excessive gain; missing shared reference; damaged IC | Power down and verify pinout, supply, and wiring. Confirm the source and circuit share a reference. Restore feedback, lower input amplitude, and check input voltages against the datasheet range. |
| Midpoint gain is not about 2 | Unequal potentiometer sections; incorrect wiper connection; saturation; loading; inconsistent RMS/peak measurement; wiring or tolerance error | Measure both effective feedback resistances with power off. Verify the wiper goes to the − input, reduce input amplitude, use one measurement convention, and inspect loading. |
| Output is inverted | Signal connected to − input; feedback connected to the wrong input; circuit is actually inverting; measurement-channel interpretation error | Trace signal to the + input and feedback to the − input. Check scope probe grounds and channel polarity. |
| Oscillation or unexpected high-frequency output | Insufficient decoupling; long wiring; op amp not unity-gain stable; capacitive load; poor grounding; feedback path routed poorly | Place decoupling near supply pins, shorten feedback wiring, improve grounding, reduce capacitive loading, and verify the device’s stability guidance. |
| Gain varies with frequency | Finite gain-bandwidth product; slew-rate limitation; parasitic capacitance; load interaction; breadboard layout | Lower frequency and amplitude separately to identify the limit; compare with the datasheet and inspect the waveform on an oscilloscope. |
| Gain control behaves backward or erratically | End terminals reversed; loose or intermittent wiper; wrong terminal used; assumption that physical midpoint means equal resistance | Identify the potentiometer terminals with an ohmmeter while unpowered. Reconnect the wiper and ends as intended, then measure the two sections at several positions. |
SPICE model and what it can show
The referenced lab’s example uses a dependent voltage source as an idealized op amp. It demonstrates the DC feedback ratio; it is not a realistic model of a 1458, 353, or other physical op amp.
Best Value
- IC Assortment contains: LM324, LM358, LM386, LM393, UA741, NE5532,NE555,PC817,ULN2003,ULN2803
- Including 10 pcs DIP4 socket, 60 pcs DIP8 socket, 5 pcs DIP14 socket, 5 pcs DIP16 socket,5 pcs DIP18 socket
- We have chosen a variety of useful IC types for daily assembly, such as: precision timers, dual operational amplifiers, audio amplifiers, Darlington arrays, quad operational amplifiers, etc.
- Anti-static plastic box, store commonly used IC kits according to label instructions
- ULN2003,ULN2803:ULN2003, ULN2803: 10 pcs Darlington array
Noninverting amplifier
vinput 1 0
r2 3 2 5k
r1 2 0 5k
rbogus 1 0 1meg
e1 3 0 1 2 999meg
rload 3 0 10k
.dc vinput 5 5 1
.print dc v(1,0) v(3,0)
.end- Node 1 is the input; node 2 is the inverting-input feedback node; node 3 is the output.
r2connects output to node 2, andr1connects node 2 to ground.rloadis the output load.e1is a voltage-controlled dependent source with a stated open-loop gain of 999 megohms in the source’s model.rbogussupplies a high-resistance path at the input node in this simplified circuit.- With
r1 = r2 = 5 kΩ, the ideal closed-loop gain is approximately 2. The supplied DC sweep sets the input to 5 V; that is a model stimulus, not a safe real-hardware test voltage. Do not apply it to a physical circuit without verifying input and output ranges.
To represent a 75% feedback-potentiometer setting as complementary sections, use Rf = 7.5 kΩ and Rg = 2.5 kΩ; the ideal gain is 1 + 7.5/2.5 = 4. This remains an idealized DC result. The dependent-source model does not capture finite bandwidth, slew rate, input offset, input bias current, output swing, supply rejection, noise, or stability. For realistic behavior, use a vendor macromodel for the exact op amp and relevant supply and load conditions.
How it compares with related circuits
| Configuration | Feedback connection | Ideal gain | Typical purpose |
|---|---|---|---|
| Voltage follower | Output connected directly to the − input | 1 | Buffering a source while providing a low-impedance output, within device limits |
| Non-inverting amplifier | Output returned to the − input through a resistive divider | 1 + Rf/Rg | Amplifying a signal without reversing its polarity |
| Inverting amplifier | Signal is applied through an input resistor to the − input; feedback also returns there | −Rf/Rin | Amplification with polarity inversion and a gain set by the resistor ratio |
The key change from a voltage follower to this adjustable-gain circuit is replacing the direct output-to-inverting-input connection with a divider. A potentiometer makes the gain adjustable for demonstration; fixed resistors are preferable when a repeatable, known gain matters.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
