# Tag Info

38

I don't have a complete answer for you, but the 8080 was one of Intel's first chips to use an NMOS process rather that the PMOS process of the 4004, 4040, and 8008 chips. In NMOS, the substrate must be the most negative point in the entire circuit, in order to make sure that the isolating junctions of other circuit elements are properly reverse-biased. So, ...

11

Contrary to popular belief this does work, but the P7805 is a DC to DC converter and it can sink current. A regular 7805 voltage regulator requires a negative supply, this does not. Here is a excerpt from the P7805 datasheet: Source: https://www.cui.com/product/resource/p7805-s.pdf

10

if I need to design a power supply for the Intel 8080, let's say using three voltage regulators, how do I prevent damages to the chip if +12v rail ramps up before -5v? With a little care you should be able to avoid that situation. the CPU draws very little current at -5V, so with an oversized filter capacitor it will naturally come up fast and go down ...

8

In the process used for the 8080, +12 provided the primary voltage for the logic, +5 supplied voltage for the I/O pin logic (which was intended to be TTL compatible, thus limited to 0 -> 5 volt signals) and -5 was connected to the substrate. The latter voltage insured that all of the active devices on the IC remained isolated by maintaining a reverse bias ...

6

You measured the loudspeakers' DC resistance at 12 ohms each, which means they're "16 ohms" speakers. Note the speakers' impedance varies with frequency, it includes an inductive part and reactive parts due to mechanical resonances, cabinet, etc. So, it is normal you don't get 16 ohms on your multimeter for a "16 ohms" speaker. Here's a "8 ohms" speaker ...

5

You can use inverting charge pump, buck-boost voltage inverter or a virtual ground op amp based solution to split rails. This is one example component which can provide $-15\,\mathrm{V}$. It is a simple dc-to-dc converter module. Part number: P7805-Q24-S15-S Do not miss to notice the pin numbering in both configuration.

4

China is similar to most of the EU. Phase-to-phase voltage for 3-phase is 380V 50Hz; Phase-to-neutral is 220V. Wye (4 conductor) and delta (three conductor) are supported; for a residence it would always include a neutral. The standard single-phase wall plug has one 220V hot and a neutral, and optionally a safety ground.

4

Bz1 is a self-oscillating warning buzzer, and the circuit around R1, T1 & Bz1 is an over-current warning. The current from the power supply drawn by the load you connect to it ends up returning through R1. When the current increases sufficiently to cause enough of a voltage-drop across R1, T1 begins to turn on which in turn causes Bz1 to buzz at you. ...

3

It is generally a diode OR circuit, a diode from the battery and a diode from the solar panel, when ever the solar panel has enough light, its voltage is higher than the batteries, so it stops it discharging and runs off only the panel, the earlier devices would also have a shunt regulator to keep the maximum solar panel voltage from getting too high, A ...

3

Here's the charge/discharge curves for that battery: It doesn't sag to 3.0V until 100% of the capacity is discharged. Note you won't get that in real life, but you'll likely get 90% while it's capacity is still fresh. Here's the full datasheet. Also, don't forget to include parasitic voltage drops. I'm not sure what you're hoping to gain with any energy ...

3

Is my thinking reasonable? No, because maximum RF input power is 23 dBm. That's 200 mW and that is all the power you could ever harvest. You can never simultaneously draw 100 mA at an output voltage of 4.3 volts. Please also remember that harvesting is never 100% efficient so you should be thinking around a maximum of 100 mW. Minimum operating power is ...

3

A typical USB charger will use a reduced-size version of a switch-mode power supply (SMPS). This kind of power supply has an isolated, low-voltage output called a SELV, or Safety Extra Low Voltage. Supplies of this type are 'touch-safe', meaning their isolation and low voltage means that contact with the secondary poses almost no hazard (leakage is below 3mA....

3

Two reasons. First, often the cell stack is already close to or well above 12V so internally the laptop would have to step up the 12V charge. Pack voltages of 11.1 and 14.4V are common. Charging these voltages is easier to manage with a step-down type regulator vs. a step-up or buck-boost. As a couple of examples, a Li-ion 11.1V (3s) battery will have a ...

3

The high frequency switching used in the SMPS can inflict some quite considerable high frequency common-mode noise on the DC output. This is due to the interwinding capacitance of the internal isolation transformer (aka flyback transformer). To reduce this noise (and obtain EMC approval) requires that the DC output is either grounded or capacitively ...

3

Measure the cold resistance of the bulbs. You’ll find that it is much lower than the wattage would imply. Incandescent filaments have a much lower cold resistance that increases as they warm up. This means that your 4.6 amp bulb will probably draw well over 10 amps at startup. Your power supply can probably supply additional surge amperage at startup but not ...

3

The 5V tolerant means you can use pull-ups in the open drain configuration, and doesn't work with push pull. This means you could possibly use a pull up to 5V and open drain, keep in mind that this method can be slower if you have too much capacitance on the digital line, the RC time constant will need to be calculated. This means if you remove the buffer, ...

3

I don't know about "any application", but most of them do have various amounts of capacitors to smooth out the supply voltage. When you power up the circuit there is an inrush current to charge those caps, which can be severe enough to cause voltage dip.

3

But the internal resistance of the voltage source is very minimal,right? If it is so minimal, then why do we have a voltage dip that is observable at the load side? It's only 'minimal' compared to the normal load current. Many loads draw much higher current when power is first applied, and then the internal resistance of the power supply is not minimal. ...

2

"Best guesstimate" is that the 12V regulator is being overloaded. You do not tell us What Vin is for the +12V regulator What heatsink you are using on the 12V regulator Bonus unknown: Heatsinking on +5V regulator. The 5V regulator with 12V in dissipates (12-5) = 7 mW/mA. So at 140 mA power dissipation is 7 mW x 140 mA = 980 mW (if Vin remains at 12V). IF ...

2

This has been a repeating theme with too few solutions during my upgrade of an industrial oven. Most PLCs use "AC Input" modules. In my observation, most EEs do not design with PLCs and will build an embedded device. I found a successful search phrase: control signal relay spdt slim 120v Other modifiers to include are DIN rail and Socket C. Any kind of ...

2

It can't because 130 W is how much the adapter can supply not how much it consume. Your car's plug only supply 1.35 A 110v but adapter needs 1.8 A (198 W ) .

2

Usually an unused comparator (like U6B) is connected thusly to keep it's output stable. If left unconnected or tied to the same rail internal noise could make it switch states randomly and perhaps quickly. However it really shouldn't be necessary as the comparator is open drain. Just leaving R22 open should give the same effect. Biasing the inputs like that ...

2

Some USB chargers uses a transformer, rectifier (4 diodes) and and LDO (or DC to DC converter). Doubly insulated power supplies might only use a rectifier and a switched power supply. The problem is several of these components use high voltage and need to be built to regulatory standards or they are likely violate local fire code. It would also be much more ...

2

In short 12V is safe to handle. Many power supplies have current limitation built in. If you know what current will be needed for your circuit you can set the current limit to that value. To do this set the current limit to zero amps. Short the + and - wires from the power supply together, set the desired voltage and turn up the current to the value you ...

2

The 220 VDC motor is (or perhaps was) chosen due to its cheap and straightforward driver implementation for any country with 220-240 Vac. Think of a triac dimmer with a bridge rectifier at the output and you have pulsating DC with approximately 220 Vdc (effective value, you could perhaps say RMS) for a 220 Vac input. Here is a schematic of a simple version: ...

2

I don't see a bypass cap on U2 -- or any of the chips, for that matter. You should put 100nF caps on all three, positioned as close as you reasonably can to the power supply leads. If that doesn't work, figure out the current draw of U2 and put a series resistor between the +5V supply and the chip, sized to drop no more than 100mV.

2

Can I connect 1-3 tp4056 module in series ? No. They will not share the voltage equally. The one that draws the least current will get the most voltage, then it will blow up and probably become a short, putting all the voltage across the other one which will then also blow up. Don't do it! I thought to use l7805 or lm317 but 1A is seemed too much for ...

2

Actually, people power RGB LED strips in parallel all the time. In fact, simply by using an RGB LED strip, you're wiring the LEDs in parallel, as all of those strips are just a bunch of parallel connected RGB LEDs with their own current limiting resistors (which is the important feature that lets them be safely connected this way). More accurately, they ...

2

Specs for linked device say 30-34V, that should be your Vfwd. LEDs usually have higher initial Vfwd until they warm up, then it drops slightly. Could be that 30V is not enough to start it up properly. Once substrate has warmed up, internal resistance drops, Vfwd with it, assuming CC. What PSU are you using? Could it be, that it has internal overcurrent ...

2

You may be getting into a "chase its tail" fold back mode with the psu. Try setting say voltage at the top end of allowed range (34V in spec sheet), current limit low and then wind up the current limit. What happens? I'd be suspicious of devices with identical V and I specs for such a wide range of colours. That doesn't mean the LEDs are not usable - ...

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