14 votes

How can I make 20-200 ohm variable resistor look like a 20-240 ohm resistor?

I have a fuel sender in my kit car that goes from 20R to earth (full) to 200R (empty). Unfortunately the gauge (constant current source, measuring resistance to earth?) expects empty to be 240 ohms, ...
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  • 159k
11 votes

Creating a verilog code for 4-bit multiplier using lookup table

There are two different ways the term "lookup table" are used in FPGA design that might be confusing you. First, the main building block of combinatorial logic in an FPGA is called a lookup table, ...
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8 votes
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MOSFET based ripple filter for tube amp

The MOSFET is acting as a source follower and this generally means that whatever signal is placed on the gate, is also seen on the source AND it is quite resiliant to ripple or movements on the drain. ...
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8 votes
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Analog analog multiplication, part of a hybrid CPU (for fun)

If you want to build an analogue multiplier that is a little off-the-beaten track then consider what happens when you feed an analogue signal through an analogue switch but control the analogue switch ...
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  • 380k
8 votes
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How is the frequency multiplied by four here?

Someone else can surely write up a better and more detailed answer than this, but: A quartz crystal is, basically, a little tuning fork that vibrates at a specific frequency, called the fundamental. ...
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7 votes
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What are some ways to improve a voltage multiplier?

You need to ditch Rd from your first schematic, and use a low impedance push-pull output as in your second schematic. However, as you correctly say, 36v will toast the gates of 20v Vgs FETs. There are ...
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  • 140k
6 votes

Which household electronics contain or used to contain photo multiplier tubes?

Sure, if you happen to have a 1955 Lincoln Continental with all the options kicking around.. they were used in the automatic headlight dimmer circuit. OPERATION: With headlights turned on, and the ...
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6 votes

Creating a verilog code for 4-bit multiplier using lookup table

In addition to The Photon's answer, here is the complete RTL of a 4-bit multiplier using LUTs. ...
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6 votes

Gilbert cell. Understanding the basic

The Gilbert cell is properly viewed as a differential-inputs EXOR gate. With 200 milliVoltsPeakPeak signals on RF and on the LO, the current-source will be strongly steered to one or the other "mixer" ...
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6 votes

How can I make 20-200 ohm variable resistor look like a 20-240 ohm resistor?

I think the easiest way would be just getting a new variable resistor. You could use a transistor to switch in an extra resistance but potentiometers are pretty cheap, so swapping out would be the ...
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5 votes

Polarized capacitors in voltage doubler

Try loading that circuit with a resistor across C1. You will find that, when delivering current to a load, its output voltage falls far below the open circuit voltage - especially if you add further ...
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4 votes
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Synthesis of a multiplier design

I presume that you are synthesising for an FPGA or CPLD. The simulator will successfully simulate many language constructs which are technically valid Verilog, but are very hard to translate to real ...
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4 votes
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GPS Antenna Selector: How to electronically select one antenna from multiple available antennas?

I believe the component you are looking for is called an RF switch. They are used for example for switching the TX path of bluetooth and wifi chips to a single antenna. RF switches are quite ...
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4 votes
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Circuits for Multiplying two Analogue Signals - AM Modulation

A simple BJT operated in the saturation region is a good start to understanding how a multiplier works: - I'm not talking about the BJT operated in the normal region (where the collector current ...
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4 votes
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Problem with accuracy of AD633 multiplier

I made very basic error. Problem was in quality of ±12V power source. After I added some capacitors, precision of those multipliers improved dramatically. Precision is within 1% now. ...
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4 votes
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Very quick Question to those familiar with analog multipliers, specifically AD633

The AD633 always divides by 10V. It says that at the very beginning of the datasheet, in figure 1. 10V is not the same as 10 without units. When doing calculations in mV and V (or indeed any other ...
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4 votes

Voltage Multiplier Frequency and Waveform

Each stage of such a voltage multiplier stacks a voltage the size of the input voltage on top of the circuit input voltage. But also, each stage has substantial losses. So the key to success is ...
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4 votes
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Do we have binary dividers circuit in CISC computers?

There are arithmetic binary multipliers and then there are clock frequency multipliers. I'll discuss some of it only, you decide what you want. For how arithmetic multipliers and dividers work, ...
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4 votes

Analog analog multiplication, part of a hybrid CPU (for fun)

These things exist - Analog devices (used to?) have some multiplier ICs you can (could?) buy. They also have this excellent appnote which I definitely suggest reading. One of the classic ...
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4 votes

Analog analog multiplication, part of a hybrid CPU (for fun)

I am just putting this out here as a viable answer for future readers. After reading Joren's answer I realized that many analog multipliers rely on matching components. So I thought to myself, why ...
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4 votes

4-bit binary multiplier circuit

You scrambled the order of the input connections on your 4-bit adder. On the submodule, you have A3 B3 A2 B2 A1 B1 A0 B0 but in your main circuit, you have them ...
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4 votes
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wrong output of a multiplier in IP catalogue

The value of 0xFFF on the output is correct. Multiplying 0x001 and 0xFF6 as 12 Bit signed integers results in 0xFFFFF6. Now you specify the output width as 12 Bit - and the uppermost 12 Bit of the ...
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3 votes

Which household electronics contain or used to contain photo multiplier tubes?

No, there are no household electronics that would include a photomultiplier tube. They are expensive, they work at high voltages, and may need to be cooled to low temps. Depending on what they are ...
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3 votes
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Polarized capacitors in voltage doubler

1) Why would people want to use polarized capacitors? Because, usually, they have more capacitance per volume and are cheaper. Search for values like 1000uF, 2200uF, 4700uF or even bigger of ceramic ...
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3 votes

How to set modulation depth with modulating a signal with an analog multiplier?

If V2 is a pure sinewave, and V1*V2=W, you aren't amplitude modulating the carrier, but DSBSC modulating it. As the "SC" in DSBSC means "Suppressed Carrier", there is no carrier energy, so the concept ...
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  • 65.8k
3 votes
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How can I increase the multiplier of a voltage doubler circuit using IC4049?

If you connect a second one like this: simulate this circuit – Schematic created using CircuitLab (only one oscillator is required, so you can use all the inverters in the second chip in ...
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3 votes
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What's wrong with my voltage multiplier segment?

It looks like you have things correctly connected, all though the top right cap isn't doing anything. The output in your case is from the bottom right corner to the top left corner, J4 to J1 in the ...
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3 votes

Independently toggling two series switches to multiply two pwm signals

I know nothing about MathLab and a little about PWM. ;^) It is known that one can synthesize a signal into a train of boxcar pulses, each with the same amplitude, if proper low pass filtration is ...
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  • 159k
3 votes

What are some ways to improve a voltage multiplier?

Replace resistor \$R_D\$ by an inductor which gives you a boost converter. That way you start the voltage multiplication already with voltage \$\gg 36V\$. But make sure that the MOSFET can hable the ...
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