Flip Flops to Divide frequency in half

[Ericwatson]

What kind of flip flop circuit divides the frequency down. They change the tranistor flip flops series in series to keep dividing the frequency. The Input a oscillator circuit to the transistor flip flops divider. The transistors are germanium.

 

[Ishaan Karnik]

JK-Flip Flop and D-Flip Flop

https://www.electronics-tutorials.ws/counter/count_1.html

 

[Audioguru]

Ancient germanium transistors in a flip flop circuit?? Why?
There are a few Cmos logic ICs that have an oscillator and digital divider with many flip flops. The CD4060 is one of them.

 

[Ericwatson]

There is 4 different types of flip flops. Discrete Silicon transistors flip flops, Discrete Germanium Transistor flip flops, TTL IC chip flip flops and CMOS IC flip flops. What is the difference between each of them. When you feedback the output to the input it divides the frequency. When using Discrete germanium transistor flip flop circuit does it change the input threshold and output frequency compared using discrete silicon transistor flip flops. The frequency is different and sound might change?

 

[Audioguru]

Why are you talking about ancient germanium transistors that have not been used for 50 or 60 years?
Go to school or look in Google to learn about the difference between geranium and silicon transistors. Also learn about the difference between TTL and Cmos logic circuits.

How can the output frequency change when it depends on the frequency of the clock input? Maybe you need to learn about flip flop dividers.

Sound? Does anybody listen to digital squarewaves?

 

[Audioguru]

Sound?
Maybe you think a simple flip flop frequency divider will lower the pitch of music or voices? Make soprano or little girl sound like an adult man with a deep low frequency voice?
No way! Music and voices are linear with many different levels and the harmonics are also at many different levels. A flip flop frequency divider is digital with only one level of its squarewaves.

 

[FvM]

Flip-flops and externally synchronized relaxation oscillators have been used as frequency dividers in antique electronic organs. May be the OP is asking about it in his vague posts.

 

[Ericwatson]

Yes in electronic organ repair they use flip flops to divide the frequency of the tuned oscillator. The flip flop divides the tuned oscillators frequency into 4 or 5 lower notes. Electronic organs use germanium flip flop frequency divider others use Silicon flip flops frequency dividers. Does this change the sound, frequency or thresholds of using germanium flip flop frequency dividers. The designers had both options of germanium or silicon at the time in the 60's, so there must be a difference as to why they used germanium flip flop frequency dividers. There is no clock signal at all in electronic organs. They use a oscillator that is tuned to a pitch note and use the flip flips to divide the frequency down to create 5 notes or frequencies lower. The way they use flip flips to divide the frequency is to take the output signal of the flip flop and feed it back to the input of the flip flop. Is there other ways of using flip flops to divide the frequency of the input signal?

 

[FvM]

I won't expect a big difference between germanium and silicium transistor circuits. The design of these circuits started when only germanium transistors were available, later they probably switched to silicium transistors which are more temperature stable. Component values have to be adjusted for different Vbe and B.

Is there other ways of using flip flops to divide the frequency of the input signal?

The German Dr. Boehm organs used synchronized relaxiation oscillators like shown in this schematic https://upload.wikimedia.org/wikipedia/commons/3/3c/Sperrschwinger.png

They have roughly a sawtooth waveform, which is preferred for sound generation due to the combination of odd andf even harmonics.

 

[Ericwatson]

So the in electronic organs the Oscillators output are a triangle waveform not a sine waveform. The flip flops output a square waveform that goes to filter networks to waveshape the square waveform into different shapes. The Flip flop frequency dividers have bias trim pot to set up the threshold voltage of the transistors?

 

[Audioguru]

I have never seen an old 60ies electronic organ that used thousands of germanium transistors in hundreds of flip flops to make the notes. In the 70ies they used a top octave generator IC that used a clock oscillator driving many digital dividers producing all the notes for the top octave, then additional digital divider ICs were used to make the lower octaves.

 

[FvM]

The transistor circuits were still present in 70th DIY organ kits.

A flip-flop won't need a trimpot, I think. The relaxation oscillators have it, and they must be tuned for a correct frequency range, otherwise they fall into a different divider ratio or operate unstable.

If you are e.g. repairing this stuff, you'll have schematics and can check the details. I'm only telling from old memories.

 

[Ericwatson]

What sets the frequency divider ratio in the flip flop circuit?

Yes, there is biasing trim pots to bias the flip flops in electronic organs. Each pitch note has a different module card that has one oscillator with a tuning inductor slug. There is biasing trim pots for the germanium or silicon transistor flip flops circuits on each module card. When using flip flops circuits to divide a frequency it uses the output frequency as a clock or trigger to be feedback to the input of the flip flop. The output is itself is triggering when the input of the flip flop is set and reset.

 

[Audioguru]

A flip flop divider divides the frequency by 2 (one octave less). Two flip flops divide by 4 (two octaves less). Three flip flops divide by 8 (three octaves less) etc in a binary fashion. It can reset itself when any output is connected to its reset input.
To understand how a digital frequency divider works you need to learn about its circuit.

 

[Ericwatson]

I'm don't know how a flip flop divides the frequency because each designer does it differently.