Bell Signal Generator Circuit

Published:2011/7/21 0:49:00 Author:Joyce | Keyword: Bell, Signal , Generator

Bell signal generator is usually a calling signal source for communication equipment. Under the control of the automatic exchange system, oscillator for sending the call will produce frequency shift calling signals for the user to choose the one needs calling. The bell signal generator is composed of frequency shift control circuit, LC frequency shift oscillator and output circuit as shown in the figure.   (View)

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Low Frequency Multi Wave Form Generator Circuit

Published:2011/7/22 21:13:00 Author:Joyce | Keyword: Low Frequency, Multi Wave Form, Generator

As shown in the figure is a low frequency multi waveform generator circuit. This circuit can output two kinds of waveform simultaneously: triangle wave and square wave. In the circuit, the first stage is a standard integrator; the second stage is a phase inverter whose gain is 1; the third stage is a hysteretic comparator. When the third stage does not have a diode, output of the circuit is positive, output of the integrator is negative inclined wave, which will turn into positive inclined wave after being inverted and will then be added to the comparator.   (View)

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Wien Oscillation Audio Signal Generator Circuit

Published:2011/7/21 21:35:00 Author:Joyce | Keyword: Wien , Oscillation, Audio , Signal, Generator

Output frequency: 20 HZ -20 KHZ. Output amplitude: 2 V.It is simple, but has excellent performance and will meet the requirement of DIY acoustic equipment. Principle of the circuit: Operational amplifier CA3140 works as the major amplifier, 100 K potentiometer and phase shifting capacitance compose phase shift, positive feedback and frequency-selective network. 1 K potentiometer and thermistor constitute a negative feedback amplitude-stabilized circuit. Audio signal is output via the follower.   (View)

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74 Series digital circuit of 74LS324 VCO (dual-phase output with controlling)

Published:2011/8/1 20:11:00 Author:Lucas | Keyword: 74 Series, digital circuit , VCO, dual-phase output , controlling)

Output frequency is determined by the external components; it can works in the frequency of 30 ~ 120Hz; if the input is added 2V voltage in the frequency controlling range, the output frequency is approximately 0.0001CEXT , and there is complementary out.   (View)

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74 Series digital circuit of 74LS3237 dual voltage-controlled oscillator(single-phase output)

Published:2011/8/1 1:25:00 Author:Lucas | Keyword: 74 Series , digital circuit , dual voltage-controlled oscillator, single-phase output

Two independent voltage-controlled oscillators; external components can determine the output frequency; it works in any frequency between 0.12 and 30MHz.   (View)

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The single knot transistor pulse transformer trigger thyristor circuit

Published:2011/7/21 3:15:00 Author:Seven | Keyword: single knot transistor, pulse transformer

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The thyristor stageless light and speed regulator circuit

Published:2011/7/21 3:18:00 Author:Seven | Keyword: thyristor, stageless, speed regulator

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The dual-thyristor controlled 3-phase heating part circuit

Published:2011/7/21 3:20:00 Author:Seven | Keyword: dual-thyristor, 3-phase

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RAMP_GENERATOR_WITH_VARIABLE_RESET_LEVEL

Published:2009/6/26 3:05:00 Author:May

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PRECISION_RAMP_GENERATOR

Published:2009/6/26 3:05:00 Author:May

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CMOS_LINE_RECEIVER

Published:2009/6/26 3:45:00 Author:Jessie

The trip point is set half way between the supplies by R1 and R2; R3 provides over 200 mV of hysteresis to increase noise immunity.Maximum frequency of operation is about 300 kHz. If response to TTL levels is desired, change R2 to 39 K. The trip point is now cen-tered at 1.4 V.   (View)

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SIMPLE_LF_CONVERTER

Published:2009/6/26 3:44:00 Author:Jessie

This converter allows coverage from 25 kHz up to 500 kHz. Use short coax from the converter to receiver antenna input. Tune the receiver to 3.5 MHz, peak for loudest crystal calibrator and tune your receiver higher in frequency to 3.6 MHz and you're tuning the 100 kHz range. 3.7 MHz puts you at 200 kHz, 3.8 MHz equals 300 kHz, 3.9 MHz yields 500 kHz, and 4.0 MHz gives you 500 kHz.   (View)

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FM_RADIO

Published:2009/6/26 3:43:00 Author:Jessie

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ANALOG_RECEIVER_LOW_TEMPERATURE_DRIFT

Published:2009/6/26 3:41:00 Author:Jessie

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TRANSMITTER_OSCILLOSCOPE_COUPLER_FOR_CB_SIGNALS

Published:2009/6/26 2:24:00 Author:May

To display an rf signal, connect L1 to the transmitter and points A and B to the vertical plates of the oscilloscope. Adjust L1 for minimum SWR and C3 for the desired trace height on the CRT. L2 = 4 turns #18 on 3/4 slug tuned rf coil form, L1 = 3 turns #22 adjacent to grounded end of L1, C1, and C2 = 5 pF, C3 = 75 pF trimmer.   (View)

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107_MHz_SWEEP_GENERATOR

Published:2009/6/26 2:22:00 Author:May

This circuit is used to observe the response of an if amp or a filter. It can be used with an oscilloscope or，for more dynamic range，with a spectrum analyzer.   (View)

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OSCILLOSCOPE_CONVERTER_PROVIDES_FOUR_CHANNEL_DISPLAYS

Published:2009/6/26 2:17:00 Author:May

The monolithic quad operational amplifier provides an inexpensive way to increase display capability of a standard oscilloscope. Binary inputs drive the IC op amp; a dual flip-flop divides the scope's gate output to obtain channel selection signals. All channels have cen-tering controls for nulling offset voltage. AL negative-going scope gate signal selects the next channel after each trace. The circuit operates out to 5 MHz.   (View)

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NOISE_GENERATOR_CIRCUIT

Published:2009/6/26 2:15:00 Author:May

The zener diode is an avalanche rectifier in the reverse bias mode connected to the input circuit of a wideband rf amplifier. The noise is amplified and applied to the cascade wideband amplifier, transistors Q2 and Q3.   (View)

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WIDEBAND_NOISE_GENERATOR

Published:2009/6/26 2:14:00 Author:May

This circuit will produce wideband rf noise. It uses a reverse-biased diode and has a low-impedance output. Can be used to align receivers for optimum performance.   (View)

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NOISE_GENERATOR

Published:2009/6/26 2:13:00 Author:May

The zener breakdown of a transistor junction is used as a noise generator. The breakdown mechanism is random and this voltage has a high source impedance. By using the op amp as a high input impedance, high ac gain amplifier, a low impedance, large signal noise source is obtained. The 100K potentiometer is used to set the noise level by varying the gain from 40 to 20 dB.   (View)

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