Normally, the dry batteries in the remote control or calculator are used for a long time and are discarded due to insufficient voltage, which is a pity.
In fact, through the following simple little circuit, these dry batteries can "extend the retirement time". . .
Cohen postado em November 7, 2020
This is a relaxation oscillator with transformer feedback. It is easier to oscillate.
But with old batteries, can't the pulse current be released?
Russell postado em November 7, 2020
Search the Internet for Joule Thief
Josh postado em November 7, 2020
Regarding the explanation of the Joule Thief, I looked at it and found it to be unreliable.
First of all, the operating voltage is as low as 300mV, which is pure imagination. This circuit is an oscillating circuit. The first reliable conduction of the triode is the key to whether the circuit can work. 600mV makes it difficult for ordinary silicon tubes to conduct reliably, let alone 300mV.
The principle explanation in the middle, people who don’t understand still don’t understand, and they will be misled. I will not list them in detail, just remind you to be cautious when reading.
The last paragraph-[Because the impedance of the inductor itself is very small, after the transistor is turned on, the inductor is directly charged and the LED is extinguished, which is equivalent to a short circuit, and high temperature is generated on the transistor. Therefore, a 1k resistor needs to be connected in series to the base to limit the base. If the feedback current is too high, it will cause the base of the transistor to break down or burn out. 】
Among them, [because] refers to the fact that when the transistor is reliably turned on, it is equivalent to a short circuit, which will generate high temperature.
No, this is when the power consumption of the transistor is the lowest, the other period of time will generate power and heat.
And [so], it is a measure to protect the emitter junction with a 1k resistor in series with the base. Of course this is correct, but it is not close to the previous [because] description.
Josh postado em November 7, 2020
Take a look at the simulated waveform.
