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)
View full Circuit Diagram | Comments | Reading(516)
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)
View full Circuit Diagram | Comments | Reading(2164)
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)
View full Circuit Diagram | Comments | Reading(603)
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)
View full Circuit Diagram | Comments | Reading(1004)
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)
View full Circuit Diagram | Comments | Reading(609)
Published:2011/7/21 3:15:00 Author:Seven | Keyword: single knot transistor, pulse transformer
View full Circuit Diagram | Comments | Reading(1185)
Published:2011/7/21 3:18:00 Author:Seven | Keyword: thyristor, stageless, speed regulator
View full Circuit Diagram | Comments | Reading(426)
Published:2011/7/21 3:20:00 Author:Seven | Keyword: dual-thyristor, 3-phase
View full Circuit Diagram | Comments | Reading(652)
Published:2009/6/26 3:05:00 Author:May
View full Circuit Diagram | Comments | Reading(0)
Published:2009/6/26 3:05:00 Author:May
View full Circuit Diagram | Comments | Reading(572)
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)
View full Circuit Diagram | Comments | Reading(1593)
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)
View full Circuit Diagram | Comments | Reading(1334)
Published:2009/6/26 3:43:00 Author:Jessie
View full Circuit Diagram | Comments | Reading(1199)
Published:2009/6/26 3:41:00 Author:Jessie
View full Circuit Diagram | Comments | Reading(968)
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)
View full Circuit Diagram | Comments | Reading(575)
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)
View full Circuit Diagram | Comments | Reading(1480)
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)
View full Circuit Diagram | Comments | Reading(792)
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)
View full Circuit Diagram | Comments | Reading(1973)
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)
View full Circuit Diagram | Comments | Reading(3009)
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)
View full Circuit Diagram | Comments | Reading(0)
Pages:130/195 At 20121122123124125126127128129130131132133134135136137138139140Under 20 |