Search found 148 matches
- Sat Feb 09, 2013 5:05 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Hi, You dont want to connect a capacitor across a switch directly as the switch shorts out the cap when it is closed. That's not that good of an idea. However, with a small resistor like 100 ohms in series with the cap, all is well. You asked about a topology earlier... You can use the op amp or if...
- Fri Feb 08, 2013 6:40 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
with Schmitt Inverter
Here is another one...
- Fri Feb 08, 2013 5:23 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Here is the debouncer circuit.
We have disused about the slew rate and rail in/out capacity of the op-amp to sync with 1ms pulses ranging from 0-5V in 0.5V steps. Can 2N2222 power transistor sync with voltage levels and timings ? Is there any better options ?
We have disused about the slew rate and rail in/out capacity of the op-amp to sync with 1ms pulses ranging from 0-5V in 0.5V steps. Can 2N2222 power transistor sync with voltage levels and timings ? Is there any better options ?
- Fri Feb 08, 2013 7:56 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Connect the Differentiator as shown with the values chosen. My mistake on the previous post. :yuck: A non electrolytic cap is fine. Steve G But as per my friend's suggestions----To realize contact debounce circuit move the cap down to be across the switch contacts that close the circuit, rather tha...
- Fri Feb 08, 2013 7:04 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Microswitch has one common point , one Normally Open point & one Normally connected point.sghioto wrote:Connect the Differentiator as shown with the values chosen. My mistake on the previous post.
Steve G
I used first two points, so What I will do with the unused third pin? Leave it opened...
- Thu Feb 07, 2013 5:28 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
I am using non-electrolytic capacitor as timing capacitor connected to pin 7 of 555. Is it OK?
- Thu Feb 07, 2013 4:54 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
I think the problem might be that capacitor C2 is too large. Change C2 to a 100nf , eliminate the diode and connect a 10K resistor across the cap which is in series with the switch. That was the circuit arrangement I used when I origionally breadboarded the circuit. Steve G c2 in series with switch ?
- Thu Feb 07, 2013 7:47 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Output
Here is my output for the circuit implemented using 555-LM324-2N2222 with Connection taken from 4.5V plug of the resister ladder. Anomalies observed: 1. Even if I have implemented one Differentiator circuit, according to the manual pushing speed of the trigger switch the 1ms output duration is 'slig...
- Tue Feb 05, 2013 4:35 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Fantastic I'm glad to see you figured it out. I don't see anything wrong with using a LM324. They are good to almost a megahz, and cheap. Steve G But I use 1ms single pulses produced by pressing the trigger switch once and next pushing may or may not be done as per the requirement of output pulse r...
- Tue Feb 05, 2013 8:22 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
I got it !
I have tested the LM324 circuit using a 2N3904 for the output and it works perfectly. :???: You must be doing something wrong. Check your components and connections again. Steve G As sghioto told, it was my mistake. I got interchanged the collector and emitter.Thanks man. Now I rectified the proble...
- Mon Feb 04, 2013 5:19 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
I am using 1ms single pulses from monoshot(with 0.5v stepped out) as the input to the op-amp and monitoring voltage at emitter on CRO.
Can OP-AMP & transistor can track the 1ms pulse change?
Can OP-AMP & transistor can track the 1ms pulse change?
- Mon Feb 04, 2013 4:23 pm
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
I have tested the LM324 circuit using a 2N3904 for the output and it works perfectly. :???: You must be doing something wrong. Check your components and connections again. Are you sure the power supply is OK? Steve G 1. OK, I will check it and report on this forum 2. Can I use the same Op Amp-2N222...
- Mon Feb 04, 2013 9:24 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
Hi, Usually when we use this kind of set up the current gain is more important so we dont mind loosing a little more voltage. If the voltage is also important, we have to switch to a different topology. Thanks for your detailed explanation, For my application voltage is also important, that is I do...
- Mon Feb 04, 2013 7:48 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Output is not following the input
I have setup the Op Amp-Current booster circuit as shown below using LM324 & 2N2222 for loads 33/68/100 Ohms one at a time. But the output voltage is not following the input as shown below: INPUT(40mA max)// EMITTER VOLTAGE// DEVIATION //SUPPLY(10V/200mA max) 0 // 0 // 0 // 10,< 100mA 0.5 // 0.4...
- Sun Feb 03, 2013 7:55 am
- Forum: General Discussion
- Topic: Emitter follower as current booster
- Replies: 57
- Views: 42629
Re: Emitter follower as current booster
What would be the output if I apply 0.5V which is less than junction drop 0.7V to Op Amp input ? Can I get same 0.5V at emitter ?sghioto wrote:The LM324 opamp regulator in that circuit is the best solution.
Steve G