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Index 25

Audi instrument lighting circuit

Published:2011/6/30 10:19:00 Author:John | Keyword: instrument

Audi instrument lighting circuit
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Automatic Broadcast Controller Circuit Composed Of 555

Published:2011/6/23 8:51:00 Author:Robert | Keyword: Automatic, Broadcast, Controller

The picture shows the automatic broadcast controller circuit composed of 555. This controller is made up of buck rectifier circuit, delay circuit, relay control circuit and so on. The F point in the picture is connected to the high-voltage indicator transformer's secondary stage's non-grounded port which is AC 6.3V. The signals of G point in the picture is from the self-monitoring signal transformer. This controller can control the electron tube loudspeaker. It would broadcast automatically according to the operating program which is booting (warm-up 2 to 5 minutes)→openning the high-voltage (the lower limit of broadcast time)→closing high-voltage (3 seconds)→closing low-voltage. If the loudspeaker is broken, it can shut down automatically after 10 seconds. (View)

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2 ~ 33MHz band-pass filter circuit formed by low-pass and high pass filter in series

Published:2011/6/20 6:31:00 Author:John | Keyword: band-pass filter, high pass filter

2 ~ 33MHz band-pass filter circuit formed by low-pass and high pass filter in series
The filter shown in the figure is not so beautiful than the above on but with equally effectiveness. This approach is to combine the low-pass part and high pass part in series. The input section is the AM-BCB filter applied above, while the output section is the same design of a 33MHz low-pass filter. (View)

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2 ~ 33MHz band-pass filter circuit

Published:2011/6/20 6:26:00 Author:John | Keyword: band-pass filter

2 ~ 33MHz band-pass filter circuit
Band-pass filter is to pass all frequencies which are higher than for those low-end cutoff frequency and are lower than the high cutoff frequency. The designed band in the shown figure is from ZMHz to 33MHz. therefore, it covers the entire HF shortwave band to eliminate interference from the LF and MWAM band and VHF television broadcasting stations. It should be noted that each part is within its own respective shield. Such is quite a good design for any multiply-section filter because it prevents the mutual influences within the components (especially the coil). (View)

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Band stop filter / notch filter resonant circuit

Published:2011/6/20 6:20:00 Author:John | Keyword: Band stop filter, notch filter

Band stop filter / notch filter resonant circuit
Band stop filter is a kind of band-stop filter with high Q value (referring to the narrow bandwidth). They are designed to filter out a single frequency signal. More precisely, they are to filter out a narrow-band signal around a center frequency. Band stop filter is used to eliminate interference of a single frequency. For example, when you are close to a FM radio station, you will find that the signals cover a large area in this band or appear on a number of frequency points in this band. (View)

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Qualcomm AM band suppression filter circuit

Published:2011/6/20 6:15:00 Author:John | Keyword: suppression filter, AM band

Qualcomm AM band suppression filter circuit
Many shortwave receivers would be adversely affected in front of the critical frequency, even if the rest parts of the receiver work well. For example, the sensitivity and intermediate frequency (IF) performance may be a good, but the third-order non-linear intercept point, dynamic range, intermediation performance are not up to the standard. If such happens, the receiver may be overloaded or without enough sensitivity or not able to obtain the desired signal. A basic source for front-end overload is the local AM band signals. Signals nearby the radio are rather strong. (View)

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AM BCB (500 ~ 2000kHz) band-pass filter circuit

Published:2011/6/20 6:08:00 Author:John | Keyword: band-pass filter

AM BCB (500 ~ 2000kHz) band-pass filter circuit
The picture shows the band-pass filter for AM broadcast band. This type of filter can be used for antenna and AM broadcast-band receiver’s antenna input terminal. It can reduce possible band signals which may interfere receiver or reduce the effects of the receiver. This filter is composed of a 2000kHz low-pass filter and a 500kHz high-pass filter in series. (View)

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band-pass filter formed by the low-pass and high pass filters in series circuit

Published:2011/6/20 6:04:00 Author:John | Keyword: band-pass filter, high pass filter

Band-pass filter is used to allow -3dB cutoff frequency with the low end and the high end. The frequency out of this range is eliminated. A simple way to get band-pass frequency’s response is to design a band-pass filter formed by the low-pass and high pass filters in series (as shown). And the cutoff frequency of HPF is designed to be equal to the cutoff frequency on the low end of the band-pass filter. Component values are calculated by the separate parts respectively. (View)