Activity for Circuit fantasist
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #278933 |
... Also, R is high enough and the current and wasted power should be small. I am not a fan of calculations but I think R could be defined as follows: R = (Vin - Vb)/(Ich + IL/(beta+1)). (more) |
— | over 3 years ago |
| Comment | Post #278933 |
@tlfong01, Thanks for the response; it means a lot to me. I have conducted an interesting on-line exercise using various web resources including Codidact. We considered this story as an example of how a BJT can act as a diode. Bb means "backup battery". Bin is the input unregulated power supply. In ... (more) |
— | over 3 years ago |
| Comment | Post #278836 |
Regarding the thermistor with NTC, maybe you mean that its temperature increases when the current through it increases. As a result, its resistance decreases and the voltage drop across it decreases thus helping the input source. If so, it can act as a "differential negative resistor" if it does it ... (more) |
— | over 3 years ago |
| Comment | Post #278836 |
@tlfong01, The "true negative resistor" here is just a "dynamic voltage source" whose voltage is proportional to R (V = -I.R) and is added in series to the input voltage so that helps it. R is the original "positive" resistance that is converted to negative resistance by adding -2VR. The true negati... (more) |
— | over 3 years ago |
| Comment | Post #278933 |
@tlfong01, I will answer you but later because after a while I will have to start an online exercise with my favorite students on how to measure the diode IV curve. They are IT beginners and I will have to discuss exactly the questions you ask. If you don't mind, we will come in here and try to answe... (more) |
— | over 3 years ago |
| Comment | Post #278933 |
@coquelicot, You probably understand that here I wanted to show something more original than usual. BTW the input source may be weak since the alarm system does not normally consume much current. But when the bell turns on and consumption increases sharply, the backup battery turns on in parallel an... (more) |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: More about "2 in 1" battery |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: Specifying |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: Structuring |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: About the BIN symbol |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: About the BIN symbol |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: More about the battery Bb |
— | over 3 years ago |
| Comment | Post #278933 |
@Olin Lathrop, I use simple conceptual circuits with a small number of generic elements. This allows me to use the rest of the space to visualize the invisible electrical quantities voltage and current. My goal is to reveal the idea and explain the circuit in order to deeply understand it. Some draw... (more) |
— | over 3 years ago |
| Edit | Post #278933 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278933 | Initial revision | — | over 3 years ago |
| Article | — |
Battery backup voltage regulator (an invention story) Goals and objectives Motivation. Inspired that there is a place on the web where simple but clever circuit ideas are encouraged, I decided to share another 1-transistor circuit trick. Besides, to make the story even more interesting than before, I decided to show, step-by-step, how the circuit w... (more) |
— | over 3 years ago |
| Edit | Post #278877 |
Post edited: More about the mechanical hysteresis |
— | over 3 years ago |
| Edit | Post #278877 |
Post edited: Describing more clearly the arrangement |
— | over 3 years ago |
| Comment | Post #278877 |
@coquelicot, OK, I have added it. Also, I have explained the connection between the button and the micro port. (more) |
— | over 3 years ago |
| Edit | Post #278877 |
Post edited: Added picture |
— | over 3 years ago |
| Edit | Post #278877 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278877 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278877 | Initial revision | — | over 3 years ago |
| Answer | — |
A: De-bouncing input signals? Another hardware solution There is another hardware debouncing technique widely used in the past. It is implemented by an SPDT push button driving (buffered by) an RS latch. SR debouncer (ganssle.com) This configuration can be thought of as an "electromechanical timer 555" since it is b... (more) |
— | over 3 years ago |
| Comment | Post #277844 |
Just to add that it is not a simple job to make a comparator with a differential input and a threshold because there are, in total, three input voltages. Two of them are single-ended (grounded) but the third (threshold voltage) is floating... and it must somehow be inserted in series with the others.... (more) |
— | over 3 years ago |
| Comment | Post #277844 |
A typical inventive solution with a scent of romance from the good old days… when simple but clever circuit tricks (Don Lancaster's "elegant simplicity") were appreciated… We can see two insights here: the first is a principle (relative instead of absolute threshold); the second is an implementation ... (more) |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Added clarification |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Restored Fig. 6 |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: About the sensor of AD example |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Replaced Fig. 6 |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Replaced Fig. 6 |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Corrected Fig. 1 |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Clarifying |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Added new tag |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Specifying |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Rearranged text |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Added another example (Analog devices) |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Rewording |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Added related WP link |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Minor edit |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Rearranged text |
— | over 3 years ago |
| Edit | Post #278836 |
Post edited: Added simple recipe |
— | over 3 years ago |