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    Capacitive dropper circuit

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    Capacitive dropper circuit

    WHONOSE, Sorry if my note wasn't clear....Yes, the IN4007 diode is necessary, I wasn't questioning that aspect. What I tried to say was that using peak to peak voltage in your calculations will produce an incorrect cap value (to low). Look at it this way. If the circuit had no diodes at-all...
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    Capacitive dropper circuit

    WHONOES, It's been almost 60 years since I first studied AC theory, but I don't ever recall using the P-P voltage as the basis for calculations in similar simple circuits. For example, if the circuit only consisted of the cap directly across the supply I would have used 230V RMS as the voltage...
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    Solder pins to small holes on my TM1637 4-digit display

    Shouldn't be that hard, those pins are not really that close together. If you accidentally bridge two pins with solder just remelt the solder and simply drag the soldering iron tip across the solder bridge. Cleaning and rewetting the tip with fresh solder may help, assuming you are using a flux...
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    A Question About PWM Controllers

    Maybe you can get away with a simple adjustable voltage convertor module. The disadvantage compared to a PWM controller is the startup torque is less. But maybe for just moving water you may not need a lot of torque. You can probably rig up some lower voltages using batteries to test if the...
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    Honda Insight battery trickle charge/discharge cycle control.

    I'm not sure of your electronics skill level, but maybe this helps? Output Q1 active on the first pulse, Q2 on the second pulse, etc... Probably needs a clean input pulse (must debounce if input is mechanical i.e., switch or relay). The output can drive a relay instead of an led or whatever...
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    Honda Insight battery trickle charge/discharge cycle control.

    To do this right probably requires a microcomputer like an Arduino and a significant effort. However a workable simple solution might be possible. Here are some thoughts. 1. Charging your battery at 100ma after a significant discharge is probably too slow unless you have a lot of time...
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    Honda Insight battery trickle charge/discharge cycle control.

    I see this post is a little old and I probably cannot help much, but with shelter-in-place I have some time to offer some comments. I think Insights have something like a 1kwh battery. Charging that at 100 ma seems pretty miniscule even for a trickle charger. Still more problematic is...
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    Philips 65 803 or LG 55C9

    Since no one else replied, I'll give you my two cents. I don't know anything about either TV, but if I wanted some insight I would find a site that sells it and read the reviews. Frank
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    Common ground

    Now, upon closer examination, I think the instantaneous voltage across the 12v cap is 24 volts. That is, in Harald's diagram D1 and D7 conduct on the same 1/2 cycle effectively putting 24v across your 12v cap. Edit: Actually it's more than 24v If you consider peak voltages. Frank
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    Common ground

    Harold, I don't see a short circuit relative to L2 or anywhere else for that matter. I think D4 is reverse biased relative to L2. Further, I don't see how that short circuit would blow up the cap that the op stated. I'm wondering if the op has inadvertently created a voltage doubling circuit...
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    TDA2030a Amplifier I.C. Specs

    Audioguru, It seems odd that the warning is for too low gain, I would have assumed higher gain is the more troublesome area. Then again, maybe that's why I am asking questions and not answering them. BTW, on my TDA2030a datasheet the tiny note is on table 7, not table 2. Just an FYI - I now...
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    TDA2030a Amplifier I.C. Specs

    HEVANS1944, Good catch, I certainly did not notice that. Actually I am using one of those Asian modules. A few months ago when I bought the module, I was torn between this module and an LM1875 module.. I see now the LM1875 datasheet is not labeled obsolete. Leave to you young whippersnappers to...
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    TDA2030a Amplifier I.C. Specs

    Yes, to replace the audio stage for my old shop radio. Seems to work pretty well, my question was more for educational purposes.
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    TDA2030a Amplifier I.C. Specs

    WHONOES, Agreed...one minor point, I would say the data sheet does imply a minimum gain..or at-least is somewhat confusing for the unwashed like myself. For example, on that same data sheet page it specifies min and max voltages and they appear to be real limits. OTOH, the closed loop gain...
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    TDA2030a Amplifier I.C. Specs

    The notation on the top of table 4, where the subject gain parameters are, says refer to the test circuit. So I'm thinking the parameters shown are not necessarily the recommended settings, but provide a example of the performance you can expect with that test circuit. Although it probably makes...
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    TDA2030a Amplifier I.C. Specs

    Bertus, Good point, I accidentally used a power gain online calculator...Using a voltage gain calculator shows that the typical application (fig 1) has a 30dB gain..Still outside the 26.5 dB max specification. I checked two other applications in the data sheet and one did fall within the spec...
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    TDA2030a Amplifier I.C. Specs

    Audioguru, Thanks for the response. Yes, I guess it could mean those dB levels are for some type of ideal performance. But It's puzzling why they would show a typical application (figure 1) with only a 13 dB gain (by my calculations). A quick look at their other applications also have similar...
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    TDA2030a Amplifier I.C. Specs

    The spec sheet for the subject IC has two specs for gain, open loop and closed loop. The closed loop gain has a min=25.5 dB, typ=26dB, max=26.5 dB. The open loop gain is 80dB typical, no min or max specified. I'm confused why the closed loop gain has such a narrow range. I interpret that to mean...
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    Measuring Current via voltage measurement

    Harald, Yup, the optimum resistor is zero. Therefore, outside the classroom using an existing resistor would be the preferred solution. Good point. Frank
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