Skip to main content

# Tag Info

## New answers tagged oscillator

1 vote

### How does this delay circuit work?

The circuit you show is called a relaxation oscillator. It's also called an astable multivibrator, which is essentially a flip-flop with phase-shifted feedback to make it oscillate. The capacitor is ...
• 55.1k
1 vote

### What is ground in a physical circuit?

The terminology commonly used in electronics is a bit unfortunate* because (at least in my opinion) it makes this concept harder that it needs to be. An alternative term for "ground" is &...
• 1,118
1 vote

### How would this circuit work with a directly heated cathode?

The original 1927 patent from Edwin Colpitts himself shows a vacuum tube oscillator with a directly heated cathode. The component symbols are different from our modern ones, but I don't think it's ...
• 408k
1 vote

### What is ground in a physical circuit?

In the physical context, all the ground symbols represent the same node. Every node which is connected to ground, using the same triangle symbol , is physically connected to every other node with that ...
• 39.2k
3 votes

### PUT relaxation oscillator problems

The circuit shown above should work without issues, and flash the LED every few seconds. There is not really much to go wrong in these circuits if you keep the divider resistance down relative to the ...
• 408k
1 vote

### How would this circuit work with a directly heated cathode?

Addressing OP's comment on another answer, Why would a choke/resistor be needed on the B+ line(apart from plate short)? Doesn't a choke basically act like a filter for HF noise? Principles used: AC ...
• 39.9k
2 votes
Accepted

### How would this circuit work with a directly heated cathode?

Yes your oscillator should work. Your little battery valves will have less transconductance so if it does not start reliably then increase the feedback and don't forget to place a choke in the B+ line ...
• 15.2k
1 vote

### Calculating capacitor charging and discharge time using LM311 as Schmitt trigger astable multivibrator

I calculate the threshold voltages at 1.45V and 2.14V using an output voltage of 0.17V (low) and 5V (high), taking into account the 1K pullup (but not the 10k to the capacitor). Simulated values are 1....
• 408k
1 vote

### Calculating capacitor charging and discharge time using LM311 as Schmitt trigger astable multivibrator

First, we need to find the threshold voltage. If we assume that LM311 is LOW (0V) then the voltage at V+ will be equal to:  V_{TL} = V_{CC} * \frac{R_2||R_4}{R_1 + R_2||R_4} = 5V * \frac{7.96k\Omega}...
• 15.2k
5 votes

### What is ground in a physical circuit?

"Ground" mainly is an abstract concept. It is the voltage node you use as a reference point for all other voltages in the circuit. Because when we say this point/trace/pin is charged to ...
• 9,669
12 votes

### What is ground in a physical circuit?

Ground is what you define as the 0V point of a circuit. So you simply have a +9V supply in reference to 0V GND and a -9V supply in referenve to 0V GND. The total supply is two 9V batteries or 18V. For ...
• 159k
1 vote

### Does PLL stabilize the frequency variations of a crystal oscillator?

With a digital PLL multiplying your reference, the MCU clock will always be N times your reference. If the reference changes 1%, the MCU clock will change 1%. 100 ppm (0.01%) variation is trivial and ...
• 169k
1 vote

### Does PLL stabilize the frequency variations of a crystal oscillator?

A PLL multiplies the running average of the input frequency over past cycles. A running average is a low pass filter, so it essentially low pass filters the rate of change of the input from the ...
• 17.6k
2 votes
Accepted

### Does PLL stabilize the frequency variations of a crystal oscillator?

If you draw a block diagram of a typical PLL, the answer becomes obvious. The frequency divider is inserted in the feedback path. PLL from Wikipedia The output frequency will always eventually follow ...
• 16.5k
1 vote

### Does PLL stabilize the frequency variations of a crystal oscillator?

A slow time constant in the PLL can filter phase noise and make the clock more stable for short time periods. But the crystal will be responsible for the long time drift (long in terms of longer that ...
• 9,669
4 votes
Accepted

### Why my RC-oscillator design does not produce any output?

first thoughts The RC phase shift oscillator is often studied in a somewhat more ideal circumstance; usually using an opamp to make things a bit more idealized. Using a single bipolar transistor as ...
• 11.2k
1 vote

### Why my RC-oscillator design does not produce any output?

If you want all three RC stages to have the same corner frequency, some modification is in order. The aim seems to be an RC product of $1k\times 100n$. You'd like R1 to be lower (ideally zero from ...
• 26.7k
2 votes

### Are these filters suitable for this application?

Are those listed filters suitable for the task? And wich one of them is better? The best solution would be to use a passive 3rd order filter as shown in the datasheet. An active filter is unnecessary ...
• 711
2 votes
Accepted

0 votes

### What is the oscillator in this 433MHz transmitter?

The LX1527 User's guide shows a somewhat different oscillator circuit that adds a surface-acoustic-wave (SAW) resonator to transistor base. It is a type of Colpitts oscillator. simulate this circuit &...
• 26.7k
0 votes
Accepted

### What requirements of a feedback network are needed to produce oscillation?

Practically speaking, such a feedback network will attenuate. Not at all if you choose the right type of topology (such as the common emitter Colpitts oscillator): - If you break the loop (dotted ...
• 465k
0 votes

### What requirements of a feedback network are needed to produce oscillation?

In short: In order to satisfy Barkhausen`s oscillation condition we have the following criteria: For a non-inverting amplifier the feedback network must be able to produce zero deg phase shift at one ...
• 27.4k
3 votes
Accepted

### Why does the voltage increase when I connect this amplifier to a gate driver?

You're going to need to drive both the high and low harder. With your circuit a current of 100 uA, which is within the gate driver's specced input high range, will drop 3.9 V across the collector ...
• 25.1k

Top 50 recent answers are included