Activity for kadamrohan16
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #291451 |
@#36396 And in case of finite gain of Q2 (e.g Beta =100) , how to approximate base current of Q2 to a resistor value which would be in parallel to R7 ? will it be R4 *(Beta +1) parallel to R7 which is 'emitter resistor reflected at base' ? (more) |
— | 7 months ago |
| Comment | Post #291451 |
@#36396 I appreciate your thorough explanation. This is what i was looking for the quick approach for such a bit complex circuits . Thevenin's voltage value comes around to be 2.7628 volts. I have one question on Thevenin application at node Vx. is it not correct to apply the Thevenins at node Vx be... (more) |
— | 7 months ago |
| Edit | Post #291450 | Initial revision | — | 7 months ago |
| Question | — |
Calculating base voltage of NPN transistor I'm having trouble using the nodal equations to determine the base voltage Vb1 in the circuit below. I've attempted to write seven equations below, but not able to fit them in entirely. Ltspice snapshot circuit (12-Vx)/1.62k = (Vx-Vy)/1.21k +(Vx-Vb1)/1k----equation 1 (Vx-Vy)/1.21k = Vy/1.21... (more) |
— | 7 months ago |
| Comment | Post #291025 |
@#52987 just to confirm ,' Demand input ' is output of op-amp ? (more) |
— | 9 months ago |
| Comment | Post #291026 |
@#36396 Thanks for the detailed explanation . will putting C1 provide faster feedback path for high speed changes at the op amp's output and hence stabilize it faster ? " R1 provides the guaranteed finite impedance for it to work against" does it mean to convey slower output changes to inverting ... (more) |
— | 9 months ago |
| Comment | Post #291025 |
@#52987 Understood . putting a RC filter with cut off frequency of 100Hz would cause the phase shift of 90 degree roughly at 10*100Hz then do i have to make sure that the 90 degree phase shift due to RC filter happens after unity gain crossing ? in case of source follower , why only 50% of gate to s... (more) |
— | 9 months ago |
| Edit | Post #291023 | Initial revision | — | 9 months ago |
| Question | — |
MOSFET drain current ringing in saturation region I benchtested below 0.7A constant current source circuit and observed few cycles of oscillation on drain current. With the help of bode plot analysis , I have managed to reduce the oscillations on drain current by increasing the phase margin to some acceptable level. Constant current circuit LTspi... (more) |
— | 9 months ago |
| Comment | Post #286952 |
@#36396
Thanks for detailed answer . I have understaing of usage of MOSFET or BJT's as switching device to be driven by digital signal. I simulated your given circuit and it clears all my doubts . (more) |
— | over 2 years ago |
| Comment | Post #286952 |
@#36396 Kindly go through below doubts.
1)The kickback voltage of 74.3V would not damage the 5V supply pin ( transceiver pin) since all the current from inductor would travel from one end of inductor and finish on other end of inductor and will not enter 5V pin? is this understanding right... (more) |
— | over 2 years ago |
| Comment | Post #286951 |
@#52987 Correct . will try this method . (more) |
— | over 2 years ago |
| Edit | Post #286950 | Initial revision | — | over 2 years ago |
| Question | — |
Technique to reset pulse transformer core quickly I am analysing a pulse transformer which is required to transfer below communication protocol pulse from primary to the secondary side. The pulse duration is 32 μs and off time available to reset the core is just 7 μs. Calculation shows that -22.85 V are required to reset the core within 7 μs. For... (more) |
— | over 2 years ago |
| Comment | Post #286494 |
@#36396
Thanks for detailed explaination .
I understood it .
(more) |
— | over 2 years ago |
| Comment | Post #286493 |
So The equation for Ib goes like
2.782 - 759xIb - 0.7 - (40+1) x 200x Ib = 0
Ib = 232 uA
This Ib is not even remotely close to the Ib observed on simulation (2.01mA) or by Kirchoffs Vtg law ( 2.09mA) .
Does it mean KVL is wrongly applied ?
Three Loops for KVL are
V1 -R1-R2.
R3-R4-R2.... (more) |
— | over 2 years ago |
| Edit | Post #286492 | Initial revision | — | over 2 years ago |
| Question | — |
Thévenins Theorem for Transistor Circuit I am calculating the base current of transistor Q1. To simplify the circuit equations, I applied the Thévenin's theorem twice and converted V1, R1 and R2 into Vth and Rth, as shown in the image. \[ \begin{align} V{th} &= V1 \times (R2/R1+R2) && & R{th} &= R1 \p... (more) |
— | over 2 years ago |
| Comment | Post #285815 |
@#36396. yes I understood the downside of the second circuit and will try the buck switcher option .Thanks. one more small doubt regarding the R1 (1K) what major role does it play in first circuit ? is it just controlling the Collector current of Q1 to ( Vbe_drop of Q2 / 1k) ? (more) |
— | almost 3 years ago |
| Edit | Post #285814 |
Post edited: |
— | almost 3 years ago |
| Edit | Post #285814 |
Post edited: |
— | almost 3 years ago |
| Comment | Post #285815 |
@#36396 Yes . Q2 will degrade over the time due to this very high power dissipation. I have another way of doing this with minimal components and complexity . Please see the alternate circuit in parent post (more) |
— | almost 3 years ago |
| Comment | Post #285815 |
Thanks for the detailed Exaplaination .
The purpose of this circuitry is to limit current through load resistor for 1 A when 150 Volts appears on the car battery . Input Voltage from Car battery varies from 30V -150V . The Choice of BJT's are not correct in this simulation but for sake of simul... (more) |
— | almost 3 years ago |
| Comment | Post #285814 |
Respected Sir ,
First of all , I sincerely apologize for all the mistakes made by me . This is my first on this forum and I assure you that I will keep in mind all the rules and process hence forth. I am following you from electronic stack exchange forum and highly admire you for your great knowled... (more) |
— | almost 3 years ago |
| Edit | Post #285814 |
Post edited: |
— | almost 3 years ago |
| Edit | Post #285814 | Initial revision | — | almost 3 years ago |
| Question | — |
PNP Darlington pair as a current limiter I am trying to analyse what is controlling the load current in the below Darlington configuration. 1. Is it the base current of transistor Q3 which is controlling current through R14 / emitter current of Q2? Image alt text 2. If it is, then is the maximum permissible load current is calcul... (more) |
— | almost 3 years ago |