# Tag Info

### I'm trying to simulate an audio amplifier circuit but I couldn't find how to add LM386 to LTSpice like image. Is there any suggestions?

What I will do here It isn't even clear to me what you actually want. One one hand, I think you may want a symbol. On the other hand, I think you may want a model. Or maybe both. I really cannot tell. ...
• 68.8k

### MOSFET gate-source protection, in selecting a Zener diode, is there any consequence of the forward voltage / current rating?

There are some problems with your assumptions. A Zener is chosen to protect the gate from exceeding its Vgs max or static max Vgss usually +/-20V so a 15V Zener is suggested. Since the static gate ...
Accepted

### MOSFET gate-source protection, in selecting a Zener diode, is there any consequence of the forward voltage / current rating?

Note that for an N-channel Enhancement-Mode MOS (NEMOS), 1.2V Source-Gate is quite low; most NEMOS will not work appreciably at this low of a voltage. So if indeed using it like this, ensure the ...
• 11.7k
Accepted

### Would appreciate some tips on designing simple OpAmp circuit

Figure 14 of the datasheet suggests that the input current into the HCPL-7840 should be fairly linear (resistor like) for input voltages in the range of -200mV to +200mV. But acconding to note 12 on ...
• 9,542

### How would one build a circuit board without hiring a manufacturer?

Assuming one had access to old cpus, ram, harddrives, and mainboards with io connections and bios chips and other chips in them. Realistic scenario, many people have that lying around. If it still ...
• 77.5k

### How would one build a circuit board without hiring a manufacturer?

Tape and etch resist pens for very simple stuff; iron-on for more complex designs. We have a Voltera for small-scale prototyping and production. The biggest thing you are going to run into is ...
• 6,530

### Is there any meaning attached to the Zener diode symbol?

I've always understood the symbol to be a stylised 'Z' for Zener. simulate this circuit – Schematic created using CircuitLab Figure 1. The 'Z' is more recognisable when the symbol is rotated. ...
• 159k
Accepted

### Designing GPS matching network with TESEO and chip antenna

Since you're using the LNA and SAW filter, you need to include the series capacitors, but they don't play a role in impedance matching. Why? The reactance of a 120 pf capacitor at 1.5 GHz is less than ...
• 2,995
Accepted

### Correct way of estimating delays in FPGAs

Realistically commercial digital logic design treats "get logic correct" and "fix timing" as two entirely separate phases of work. It's even more extreme in ASIC design than FGPA, ...
• 44.9k
Accepted

### TEC cold side temperature decreases, then increases rapidly

Peltier units are extremely inefficient. This means that for every watt of heat you move, you generate several more watts of heat in the unit. The hot and cold side are physically coupled together. ...
• 7,232

### Would appreciate some tips on designing simple OpAmp circuit

from datasheet ... Description The Broadcom® HCPL-7840 isolation amplifier family is designed for current sensing in electronic motor drives. In a typical implementation, motor currents flow through ...
• 3,618

### Why a diode is in parallel with the current source in the equivalent circuit of a solar cell?

I know I'm four years late, but none of the other answers here acknowledges that the diode in the model actually is real. A conventional PV cell *IS* a giant PN diode, and the current source in the ...
• 2,285
Accepted

### How would one build a circuit board without hiring a manufacturer?

It used to be common for electronics hobbyists to make their own circuit boards. The equipment needed is essentially:- Copper-clad boards. These are PCBs with a continuous layer of copper across ...
• 14.6k

### Is there any alternative mechanism of using 7 relays?

You can do it with 4 two pole change over relays or just 3 if you have a 4 pole changeover relay available. Relays 3 and 4 are driven together if two pole changeover ones are used. Four pole ...
• 29k

### Can this circuit with two resistors oscillate?

It doesn't oscillate. It only has current opposite to the instantaneous voltage. There is no feedback effect, so no oscillation.
• 10.2k

### Can this circuit with two resistors oscillate?

This theoretical condition produces an infinite current (or a singularity) when R+ & R- = 0 and thus an infinite voltage across either resistor for any input voltage from a theoretical ideal ...

### Can this circuit with two resistors oscillate?

Quote (emnha): ....I'm interested in the theory if two R, -R can oscillate with frequency unspecified No - this is imposible because this would violate the oscillation condition which requires that ...
• 22.5k
1 vote

### Function generator with an operational amplifier

Some things: a. Without some form of feedback from the triangle output to the square wave generator, the integrator will eventually saturate either nigh or low. this is because the output stage of a ...
• 12.5k
1 vote

### Circuit that switches on at 4V and off at 3V

Try this for a start. It is important that the circuit itself draws low current from the cell. This circuit is cheap and acceptable exact. A diode is used as reference voltage here, this has a ...
• 126
1 vote

### Connecting two motors to one Arduino board

No. The buttons are wired incorrectly. They most likely won't do anything at all. You would need a pull down so that the "resting position" of the input is low. Your buttons could then ...
• 57.4k
1 vote

### USB-C passthrough (including CC line) not making connection

The CC pin connections are not correct. Sure, there is only one CC wire in the cable itself. The other CC pin that is not wired 7n the cable is pulled down to ground via a resistor by the cable, in ...
• 87.1k
1 vote

• 9,658
1 vote

### How can KCL be satisfied here?

Think about reasons why Vbe would decrease. It could be caused by lower base current as you suggest. The requirement for that is either RB increasing, VCC decreasing or Id increasing. Vbe could also ...
• 1,518
1 vote

### Using a square wave function to select output

One idea is to use a single pole double throw (SPDT) analog switch IC such as this Select which input (B0 or B1) is connected to the output A by the logic level of S. Make sure the signal is in range ...
• 66
1 vote

### How can I control a firework igniter (e-match) with Arduino?

A more powerful battery is surely not enough. An Arduino can supply only tens of milliamps where an e-match might draw a few amps. Just drive an Arduino relay module and let the output of the relay ...
• 111
1 vote

### Switch off 2 power supplies using a single switch in a feedback loop

One way to make this work is to split the LEDs to only the way one is powered off of the second battery. In this case, you can use the switched first battery to operate the relay, acting as the switch ...
• 7,070
1 vote

### Switch off 2 power supplies using a single switch in a feedback loop

The lights look great! I have done similar things in my house. Is it possible to increase the voltage, if not ok. In my proposed solution the increase in voltage will reduce the current in the wire ...
• 2,553
1 vote
Accepted

### Buck converter bias supply

The $V_{CC}$ pin on the MP2325 is brought-out for the externally applied smoothing capacitors. Up to 5 mA can also be drawn from $V_{CC}$ for (say) the PG pin: - The red-lines in the image above ...
• 378k
1 vote

### Water level indicator using CMOS inverter

This won't actually work. When the water reaches each electrode, the voltage will be pulled low, the corresponding inverter will be high and its LED will illuminate. But when the water has not reached ...
• 12.4k

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