CircuitShepherd @CircuitShepherd Twitter profile | Pikagi

Pikagi

CircuitShepherd

@CircuitShepherd

8,377

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177

Following

159

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340

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I create electronics and Apple apps. Analog design superpowers: Sketching:

Austria

https://t.co/ZSNCxHdV0O

Joined January 2022

Don't wanna be here? Send us removal request.

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

1 year

Never underestimate the power of automated parameter optimization! CircuitShepherd provides you with analog-design superpowers by doing it in realtime! It enables a fast workflow that has never been seen before! Join the mighty dark side of intuitive circuit engineering now:

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

6 months

Insert a resistor in series with a capacitor into your transistor amplifier circuit to adjust the small-signal gain without affecting the operating point:

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CircuitShepherd

@CircuitShepherd

7 months

Turn a linear potentiometer non-linear by adding a resistor between the slider and an outer terminal!

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6 months

Use a string of mirrored current sources to adjust them all with a single analog potentiometer:

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CircuitShepherd

@CircuitShepherd

1 year

What's Vout? 1V, 2V or 3V?

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6 months

Cascade Opamps to dramatically increase the bandwidth of your amplifier circuit:

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6 months

Which switch would damage the circuit if opened? S1, S2 or S3?

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CircuitShepherd

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6 months

Which circuit won't work? A, B, C or D?

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@CircuitShepherd

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1 year

What's Vx? 2V, 4V or 8V? Assume a very high current gain of the transistor by neglecting the base current.

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5 months

Synthesize a voltage source and series resistor with a simple voltage divider to add an offset to your opamp amplifier circuit:

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1 year

Which DC sweep plot is correct? A or B?

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6 months

What's R3? 10k, 20k or 30k?

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1 year

What's R1? 12k, 24k or 36k? What's R2? 10k, 20k or 30k?

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6 months

If you accidentally swapped the collector and emitter in your PCB design, simply adjust the base resistor to maintain a low Vce:

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CircuitShepherd

@CircuitShepherd

1 year

What's Vout? 0.9V, 1.2V or 1.5V?

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CircuitShepherd

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1 year

What's Vec? 6V, 8V or 10V? Assume a very high current gain of the transistor by neglecting the base current.

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1 year

What's Vout? 12V, 20V or 24V? Assume a very high current gain of the transistors by neglecting the base currents.

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CircuitShepherd

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1 year

What's R1? 10k, 20k or 30k?

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2 years

Find R2!

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1 year

Opamps in CircuitShepherd are modeled by a voltage controlled voltage source (VCVS) and an output resistance. "AOL" (open-loop gain) and "Rout" (output resistance) are changeable properties. In case of AC-simulations the VCVS also has a frequency dependence defined by the

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6 months

Which circuit does not have a small-signal gain of -10? A, B, C or D?

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2 years

Find R2 of this comparator circuit:

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2 years

Which bode plot is correct? A, B or C?

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

1 year

Which circuit is correct? A, B or C?

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2 years

Which bode plot is correct? A, B or C?

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@CircuitShepherd

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2 years

Which bode plot is correct? A, B or C?

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CircuitShepherd

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1 year

What's Vout? 4.9V, 5.9V or 6.9V? What's Ix? 3mA, 4mA or 5mA? Assume a very high current gain of the transistors by neglecting the base currents.

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1 year

This is a 3-band audio equalizer circuit! Which potentiometer adjusts the bass? P1, P2 or P3?

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1 year

What's Ix? 6mA, 10mA or 15mA? Assume a very high current gain of the transistors by neglecting the base currents.

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1 year

What's Ix? 10mA, 12mA or 15mA? Assume a very high current gain of the transistors by neglecting the base currents.

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CircuitShepherd

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1 year

For slow changes of Vin, the small-signal gain is approximately -1. What's the small-signal gain for fast changes? Is it approximately -1, -2, or -4? Assume the transistor to have infinite bandwidth.

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2 years

Which DC-sweep plot corresponds to the given transistor circuit? A, B or C ?

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1 year

Tutorial 3/7: Designing Simple Lowpass Filters

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1 year

Tutorial 5/7: Designing Inverting Opamp Circuits

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1 year

What's R2? 1k, 2k or 3k?

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2 years

Estimate R1. 10k, 11k or 100k ?

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1 year

This is a non-inverting summing amplifier! What's Vout? 3V, 4V or 8V? How can R4 be modified for a 6V Vout? 20k, 30k or 40k?

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@CircuitShepherd

CircuitShepherd

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1 year

🔥One-time App Store only promo experiment! Full version of CircuitShepherd for $0.99/1st year instead of $2/month. A deal that will never repeat! Act fast 👉

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CircuitShepherd

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2 years

Which comparator based Schmitt Trigger circuit corresponds to the given hysteresis? A, B or C?

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1 year

What's Iout? 1mA, 2mA or 4mA? Pro-level discussion: Is this circuit stable? What are possible pitfalls regarding to stability?

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11 months

What's Vout? 4V, 5.3V or 6V? What's Vgs if Vin = -6V? -4V, -2V or 0V?

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1 year

What's Ix? 2mA, 3mA or 4mA?

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1 year

Which circuit is correct? A, B or C? (Assume an ideal op-amp.)

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1 year

Which Bode plot is correct? A or B? Assume the transistor to have infinite bandwidth.

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CircuitShepherd

@CircuitShepherd

1 year

Which circuit is correct? A, B or C?

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

1 year

New CircuitShepherd release now available on the App Store, Google Play, and Desktop! Added new features to set up AC simulations with non trivial stimuli like multi-phase systems (see screenshot for an example). Here is the full changelog: Version 1.8.1 - 23 May 2023: Added a

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1 year

What's the small-signal gain for lower frequencies? 1, 2 or 3? What's the small-signal gain for higher frequencies? 4, 5 or 6?

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CircuitShepherd

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1 year

Which circuit is correct? A, B or C? (Assume an ideal op-amp.)

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2 years

Which passive filter circuit has a bode plot, most similar to that of the active filter circuit? A, B or C? Assume an ideal op-amp with infinite bandwidth.

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2 years

Find R2! 1k, 2k or 4k?

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2 years

Which switch would NOT turn off the LED if closed? S1, S2 or S3?

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2 years

The correct answer is C 😉 The video shows how to modify the circuit to meet another Thévenin equivalent of 5V and 30kOhms, while a side condition of R1+R2 = 20kOhms is maintained 😎

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1 year

Which circuit is correct? A, B or C?

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2 years

Which inverting opamp circuit corresponds to the DC sweep plot? A or B? Note: The alpha value of the potentiometer is plotted on the horizontal axis.

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2 years

Which switch would harm the LED if closed? S1, S2 or S3? Assume that the LED will be harmed at a current > 20mA.

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1 year

What's R1? 10k, 15k or 20k? What's R2? 30k, 40k or 50k? #voltagedivider

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CircuitShepherd

@CircuitShepherd

2 years

Which Thevenin equivalent circuit is correct? A, B or C?

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11 months

What's the equivalent input resistance of an ADC with a Sample & Hold capacitance of 20 pF operating at a sample rate of 500 kHz? 1k, 10k or 100k?

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1 year

Tutorial 1/7: Designing Voltage Dividers

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1 year

What's R1? 10k, 20k or 30k? What's R2? 30k, 40k or 50k?

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2 years

Which resistor consumes the least power? R1, R2, R3 or R4? (Don't calculate, just argue!)

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1 year

In CircuitShepherd, you have two modes for measuring the small-signal gain: HF (high frequency) and LF (low frequency). The HF mode measures the small-signal gain for fast changes of the input signal, while the LF mode measures the small-signal gain for slow changes of the input

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1 year

Tutorial 4/7: Diodes, Comparators and Discontinuities

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1 year

Which circuit is correct? A, B or C?

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2 years

Which capacitor would you remove to fix this faulty opamp circuit? C1, C2, C3 or C4?

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1 year

What's Ix? 1mA, 2mA or 3mA?

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6 months

I also recommend the video 'Cascading Opamps For Increased Bandwidth' from @eevblog

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2 years

Estimate the current through R4! 1mA, 2mA or 4mA?

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@CircuitShepherd

2 years

Estimate Vout! 2V, 4V or 8V?

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6 months

Use CircuitShepherd's optimizer to find the value of the gain resistor R5:

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7 months

Add resistors in series with a potentiometer to limit the adjustable range! What's R1? 10k, 20k or 30k? What's the adjustable range?

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2 years

Which circuit is not a current mirror? A, B or C? (For the current mirrors Iout = Iprog)

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2 years

Which resistor needs to be increased to get a smaller hysteresis? R1, R2, R3 or R4?

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2 years

Which bode plot is correct? A, B or C? #opampCircuit

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2 years

Which bode plot is correct? A, B or C? (Missing trace labels are part of the puzzle.)

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6 months

Use CircuitShepherd to find the resistor values for a specific overall gain:

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2 years

Estimate Vout! 6V, 12V or 24V?

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CircuitShepherd

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2 years

Which switch would double the LED current if closed? S1, S2 or S3?

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2 years

Which DC sweep plot would be correct if S1 is closed? A or B?

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CircuitShepherd

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1 year

Tutorial 7/7: Designing Schmitt-Triggers

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CircuitShepherd

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1 year

Estimate R1 of this non-inverting opamp circuit! 10k, 20k or 30k? (Hint: Substitute R2 and R3 with its Thévenin equivalent.)

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CircuitShepherd

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2 years

Estimate Vout! 8V, 16V or 32V? #opampCircuit

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CircuitShepherd

@CircuitShepherd

1 year

What's R2 of this non-inverting opamp circuit? 5k, 10k or 20k? (Hint: First find the Thévenin equivalent of R2 and R3.)

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CircuitShepherd

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2 years

Which component consumes the most power? T1, T2, R1, R2 or R3?

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

7 months

How to design any second order passive RC-lowpass (PT2) in seconds: 1. Select the “second order RC lowpass” template. 2. Select the voltmeter. 3. Adjust the “f [Hz]” to the desired 3dB corner frequency. DONE!

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CircuitShepherd

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6 months

Add another optimization target at the desired corner frequency to find the value of coupling capacitor C2:

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CircuitShepherd

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1 year

What's R2 of this FET #currentsource ?

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CircuitShepherd

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1 year

Estimate R2 of this inverting opamp circuit! 10k, 20k or 30k?

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CircuitShepherd

@CircuitShepherd

6 months

Use the wattmeter for an instant overview of the circuit's power dissipation:

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1 year

Which Thevenin equivalent circuit is correct? A, B or C?

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CircuitShepherd

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2 years

Estimate R4 of this Summing Amplifier! 1k, 2k or 3k?

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CircuitShepherd

@CircuitShepherd

1 year

Pro Tip: In CircuitShepherd, you can measure any small-signal gain around the actual operating point by selecting either the "HF" or "LF" mode!

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6 months

I also recommend the video 'Back to Basics: Transistor Current Sources and Mirrors' from @AlanAtTek :

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CircuitShepherd

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2 years

Estimate Vout! 0V, 1V or 2V?

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CircuitShepherd

@CircuitShepherd

1 year

Tutorial 6/7: Designing Non-Inverting Opamp Circuits

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CircuitShepherd

@CircuitShepherd

1 year

Estimate R2 of this comparator based non-inverting Schmitt trigger circuit! 10k, 20k or 30k?

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CircuitShepherd

@CircuitShepherd

2 years

The correct answer is A 😉 The video shows how the bode plot changes with the damping resistor R2 😎

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CircuitShepherd

@CircuitShepherd

2 years

Which bode plot is correct? A, B or C? Assume an infinite gain-bandwidth product of the opamps. (You may know this circuit as the input stage of an instrumentation amplifier.)

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1 year

What's Vout if S1 is closed? 3V, 4V or 5V?

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CircuitShepherd

@CircuitShepherd

2 years

Which Thevenin equivalent circuit is correct? A, B or C?

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@CircuitShepherd

CircuitShepherd

@CircuitShepherd

2 years

Which circuit has a unique Thèvenin equivalent? A, B, C or D?

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