# Tag Info

## New answers tagged circuit-analysis

### Analyzing a circuit with 2 voltage sources

I don't know if this helps, or if it would be an acceptable solution to your professor, but I notice that the circuit is completely symmetrical either side of R3. That means you could split the ...
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1 vote

### Do you know this circuit?

The 2 PNPs form a simple comparator; comparing the emitter voltages. When the 3V3 level is higher than ext_3V3, the right-hand PNP will have a higher VBE than the left-hand one (since the bases are ...
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### RC Integrator Simulation

Simply put, when you use a VCCS model, you are assuming a transconductance amplifier (like a 5T-OTA) which inherently has a large (ideally infinity) output resistance. Under such conditions, the ...
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### Why does a MOSFET fail on fast signals, even if they're much longer than the turn on + turn off times?

While you may not have drawn a resistor in series with V2, the mosfet model most certainly contains one. See LTSPICE wiki: https://ltwiki.org/LTspiceHelp/LTspiceHelp/M_MOSFET.htm which in the table ...
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### How do I analyze an emitter follower with a capacitive load?

how can I predict the emitter voltage or current? Generally, you'd do it by solving the differential equation system that models the circuit. SPICE does it numerically. You may be able to come up ...
Accepted

### How do I analyze an emitter follower with a capacitive load?

Since the transistor is only able to source current from the positive supply, implying current flowing downwards through the capacitor, and since you've provided no way for current to flow upwards ...
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### Why is a push-pull transistor configuration asymmetric?

Each transistor is responsible for passing current in two different parts of the input/output waveform, between which current in the load changes direction. The upper transistor is allowing current to ...
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### Why is a push-pull transistor configuration asymmetric?

Everyone has already pointed out that one of your transistors is arranged incorrectly. So I won't belabor it here. Sufficient that you know it won't work. The phrase ...
• 11k

### Why is a push-pull transistor configuration asymmetric?

Your circuit is invalid. Try something like this. It can operate from a single-ended power supply. Reference the amp to 6-volts. Circuit reference https://circuitdigest.com/electronic-circuits/push-...
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### Why is a push-pull transistor configuration asymmetric?

But that's not a valid push-pull circuit to begin with. You have the PNP transistor upside down. Even if it were correct, for negative output you would need a negative supply and you don't have one. ...
• 157k

### How do I analyze an emitter follower with a capacitive load?

The problem is that you're trying to linearize about a DC bias where the transistor is deep into cutoff, because there's no way for C2 to discharge. The emitter voltage is pinned to Vcc, and you're ...
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### How do I generate a trigger signal from a periodic analog signal having varying amplitude

I would use the following: Since you want a threshold relative to the signal's amplitude, first decide if this is RMS, average, or peak amplitude, and use the corresponding detector on the signal to ...
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### How do I generate a trigger signal from a periodic analog signal having varying amplitude

Of course, it's impossible to have the circuit trigger as some point on the rising edge of its own cycle, since you can't know what the peak amplitude is until you reach it. You could sample the ...
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### How do I generate a trigger signal from a periodic analog signal having varying amplitude

With edge triggering, you generally have two main levels: the arming level and the firing level. When your signal passes the arming level (e.g., a 0V DC offset sinusoid rises above 0V), your system ...
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### Load cycler circuit analysis

You might more simply connect the battery to either load or charger as shown here. simulate this circuit – Schematic created using CircuitLab
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1 vote

### Frequency compensation circuit

Your circuit is a high pass filter. The time constant of the circuit can be found by looking at the circuit from the capacitor’s point of view. The capacitor sees R an Rc in parallel. The time ...
• 1,600
Accepted

### Where am I wrong in my derivation of RC charging circuit equation?

KVL states that sum of all voltages in series is zero. There is a constraint: The voltages of each element must be measured with the same orientation. The diagram aligns the voltages with the ...
• 16.8k
1 vote

### What is the purpose of the BJT in this circuit?

There are many good answers already, but I think one key point is missing: an external BJT is used because it has better heat dissipation and power handling. The purpose of the Zener voltage reference ...
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### Where am I wrong in my derivation of RC charging circuit equation?

The main thing is you lost track of the polarity of your voltages. A diagram can be very helpful in keeping track of this. From your first point about KVL — $V_B + V_R + V_C = 0$ — you have: ...
• 175k

### Where am I wrong in my derivation of RC charging circuit equation?

The error is introduced in the integration, because the resulting equation has voltage unit on left side and no unit on right side.
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