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131 Threads found on Variable Capacitor
The datasheet shows the oscillator variable capacitor (to tune the frequency) connects to pins 18 and 19. The RF variable capacitor (to peak the sensitivity at a frequency) connects to pins 19 and 20. If you replace the trimmer capacitors then the replacements must have the correct capacitance value. With (...)
Apparently it's a dual variable capacitor, as used in many classical radio receivers. There seem to be four trimmer screws accessible through the PCB. In case of a superhet receiver (presume it is), the matching of both capacitors, respectively the capacitance ratio, is essential for receiver performance. What are you trying to modify?
The AC induction motor may be three phase, capacitor start or a shaded pole type. If you need a precise speed, you need to have a motor with built in feedback. Some of them can be used as position sensor. The current fashion is a vfd- variable frequency drive- it works like a charm on three phase drives. They tend to be more complex. Give more
"voltage < or > ground" can be a DC offset which doesn't change the "effective" capacitance. Or a variable voltage depending on the capacitor voltage (generally a*Vcap). Miller and similar effects are observed only in the second case.
Hi, I need to develop a circuit that oscilates at fixed 100MHz between points A and B Points A and B have atached a variable capacitor from 10pF to 500pF. capacitor variable need to be proportional to DC out at fixed 100MHz between probe A and B. Capacitance meter at 100Mhz to DC out proportional. Check this picture (...)
Hello Everyone! I've a degree in Power Electronics and I'm trying to build a charger with variable output 0-80V and 0-50A aproximatelly. Now I'm stucked with high currents to charge up the large capacitor that I have on the output. I have made and I attach the simple schematics of what I'm having right now. I'm controlling the output volt
124501 Like this circuit Mv1 and Mv2 transistors have their source and drain tied together. What's the purpose. this is VCO circuit, CVar , variable capacitance is measured from which node? X or Y? and that's the output of the VCO?
If this is a free running pulse train (which 1GHz implies) then maybe a capacitor-blocked, DC-restored inverter is your ticket. See this scheme in CMOS RF prescalers (single ended) on PLLs and such. It will burn some excess power but probably no worse than other schemes. Unbalanced or variable duty waveforms, or ones where you need the DC state
Be aware of the self capacitance of the inductor, it can give misleading results. In a RF Q meter, your U is a known current delivered through a very low value resistor (.04 ohms). In series with the earthy end of the L there would be a variable capacitor with a high impedance volt meter across it. So you energise it at a known frequency, and measu
I believe it should be easy to calculate ignition coil current waveforms and required dwell time to reach a specific coil current. Historically, cars had mechanical ignition contacts with fixed dwell angle and thus strongly variable dwell time. Coil current at low engine speed was respectively limited by the coil resistance. At high engine speed
I want to couple a mosfet to a microstrip line and use it as variable capacitor by varying Vgs.But I don't know how to start with the circuit.Can any body guide me?
Hello, i would like to know how i can model a varistor and a variable capacitor depending on voltage. thanks in advance Check the elements on the "Eqn Based-Nonlinear" palette. There you find general equation-based elements and a non-linear capacitor.
A quite simple method: Using a frequency variable sinusoidal generator (with a series resistor such that R>>wL and a decoupling C), and an oscilloscope or an AC voltmeter, measure the resonant frequency of the inductor with a fixed capacitor (frequency that gives maximum voltage in the parallel LC). With current flowing across the inductor (using
It's somewhat funny question, but here it goes. You can find them on HAM radios - it's like a variable capacitor for tuning, but it can be rotated as much as you want. It's used for setting the frequency on digital radios. It just keeps on rotating, doesn't even stop on 360 degrees, you can make as much turns as you want.
hii i write this verilog-a for variable capacitor and i test circuit in hspice but capacitor don't change While i expected capacitance change sinusoidal please help me `include "constants.vams" `include "disciplines.vams" module vccap(Cp, Cn, Vp, Vn); input Vp, Vn; inout Cp, Cn; electrical Cp, Cn, Vp, Vn;
What is the difference if I just use 1 variable capacitor? Your resolution will be a factor of 10 worse (50..55 instead of 0..5 pF).
hi i decide simulate this circuit in hspice but i can't modeling variable capacitor section pleeeease helllp me 117330
Hello, in this multibibrator if the neon bulb is replaced with a variable capacitor and a suitable RF transformer is used, RF damped waves are produced frequency is determined by the resonance of the LC and the d
When you're asking for variable capacitors with 0.01 pF minimal value, did you already estimate the bare pad capacitance? The idea sounds rather unwordly.
The formula is for minimal bootstrap capacitor (an inequality in mathematical terms), so the answer in case of a variable time period should be clear.