Geez, I like long videos... Seriously thanks for the topic because I have been meaning to experiment with the scheme. Sooner or later I'll grab some screen shots of your experimental circuit and have a go with the concept. I am always looking for elegant ways to get more linear amplification out of fairly simple and low cost devices and this scheme looks very promising.
Nice job, you explained it pretty well, but I think if drew the ckt using the Hybrid-pi model and did the pertinent loop equations it might help some of the younger players to really get a better insight on what is really going on here. Just a thought, again excellent job and thanks for sharing.
I was wondering, (although i guess it will be explained in the next video) ... but I noticed that in many circuits that use the the Sziklai pair, there is also often a resistor between Q2's base and emitter. Is that for the same reason as in the Darlington pair?
Please also explain how the single stage amplifier using transistor at the output of chips like Um66 or Um3561 used for amplification functions & also how we can design such circuit if we need to increase the output power (calculate the watts) of those Siren type circuits in some another video
I have to get from 5V signal a Electric motor working this Electric motor needs ~12V and 1A .. i have to use BD676/5 Darlington-Transistors … can u help me please? i don't know how big is the reinforcement for the Transistors how can i find that our without to measure .. from datasheet ?
JohnAudioTech+ Do you have any plans for a 2.1 Class D Amp 50+50+100 amps we could do? and what your favorite brand of capacitors and mosfets if money wasn't a issue? Thanks.
Do you mean testing a class D board or building an amp from scratch? I don't have any favorite brands. Whatever works and is of good quality is good enough for me.
hi, can you please explain to me why there is no resistor connected between the emitter of the first transistor and ground. what will be the implication of connecting one? will have an effect on the gain achieved? thanks
If the device providing the signal to the base can't sink current well to pull stored charge out of the transistor, it will slow it down. Adding a resistor in that case can speed it up at the cost of lower input impedance.
Thanks for the quick response. myself and a few colleagues are trying to build an FM transmitter just for demonstration purposes. one of us thought by using a Darlington pair we will bust up the power to the antenna. one of the key requirements is to put that resistor on emitter the first transistor to ground and also use the same transistor with the same hfe. Do you think this is the correct line of thinking? Thanks.
Exactly. Darlington configuration does that because the collectors are connected together. Instead, two separate transistors with the collectors separate should be used. Then the second can fully saturate and not waste so much power.
HELLO THERE . THERES A TIP142 NPN TRANSISTOR IM TRYING TO USE IN MY ONE TRANSISTOR SOUND AMP . SO TELL ME WHERE IS THE EXIT IS IT AN EMITTER OR COLLECTOR ???
Dear John is there any instrument you have to measure a signal 10 mV with 1% accuracy?10 mV +/- 2% x 5000= 4900 to 5100. So practically 5100 gain and 5000 are not distinguishable .Giving the fact that gain of transistors are among many E current , CE voltage and temperature dependent so you need to add many more error factors too.The result becomes so uncertain that when you drawn yourself in theory of physics you may loose the point.
3:38 The current that is near the collector of Q2 is 505mA and the emitted current by the Q1 is 10.1, so shouldn't the emitted current by Q2 be 10.1+505=515.1?
@@TheJokerandTheJean The Beta formula is correct. The gain in the example is 5150. The emitter current is 515.1 ma because it is inclusive of the .1 ma base current going into Q1. Beta is calculated using the collector current, not the emitter current.
