This circuit uses a protective resistor R2 in conjunction with feedback resistor Rl. Together, they form a voltage divider to reduce the input voltage amplitude for ICl-a so that the protective diodes never conduct. ..
The DG419looks into the high input impedance of the op amp, so the effects of Rvs(o"l are negligible. The DG441 is also connected in series with RIN and is not included in the feedback dividers, thus contributing negligible Views: 3 | Votes: 52 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Mar 21, 2013 |
The Signetics NE5204 or NE5205 can be used in this AF to 350-MHz (-30 dB) preamp. If 600 MHz @ 3 dB is needed, use the NE5205. The noise figure is 4.8 dB at 75, 6 dB at 50 . ..
In applications where the period of the input pulses is uneven and the divider is required to cover a wide range of frequencies, the non-integer programmable pulse divider shown can be used. The purpose of the D-type flip-flop (IC2) is to synchronize the input signal with the clock pulse. When the clock pulse changes from low to high and the input is high, IC2 output goes high. Subsequently, IC3 resets to zero and starts counting up...
The 741 has a maximum gain of 20,000, but the circuit is so designed that the IC"s gain is 2,700,000 which then distorts the output. This distortion gives the fuzz effect. The two diodes clip the output to drop the level, also lowered by the potential divider..
The circuit is a light switch who triggers when light drops on photo resistor. It is fairly simple in construction and can be used in a million applications. The photoresistor and the trimmer work as a voltage divider and also polarize the transistor TR1. TR1 triggers TR2 and TR2 drives the relay. Trimmer R7 is for adjusting the sensitivity of the circuit. ..
The LM39X4 acts as a LED-driving vol-tometer that has its basic maximum and minimum readings determined by the values of R2 and RV2. When correctly adjusted, the unit actually covers the 2 volt to 3 volt range, but it is made to read a supply voltage span of 10-10 volts to 15 volts by interposing potential divider R1-RV1 between the supply line and the pin-5 input terminal of the IC. The IC is configured to give a "dot" display, in which only one of the ten LEDs is.....
The circuit exploits the fact that when fed from a constant current source, the forward voltage of a silicon diode varies with temperature in a reasonably linear way. Diode Dl and resistor R2 form a potential divider fed from the constant current source. As the temperature rises, the forward voltage of Dl falls tending to turn Ql off. The output voltage from Ql will thus rise, and this is used as the control voltage for the CMOS VCO..
This circuit is meant to be driven by a 1-MHz standard signal of a few volts amplitude. Ul through U5 are 7490 decade counter/divider and produce a division ratio of 100,000:1. Successive divisions of 10 can be tapped off, if desired, between stages. ..
This circuit offers 10- to 15-dB gain from 400 to 850 MHz and is therefore eminently suitable for situations where th..
This wideband antenna preamplifier has a gain of around 20 dB from 40 to 860 MHz, covering the entire VHF, FM, commercial, and UHF bands...
This ultra wide range timer uses a 555 timer base, two 4017Bs and a 4020B that act as frequency dividers that can be switched in and out...
An inexpensive. antenna-mounted, UHF-TV preamplifier can add more than 25 dB of gain. The first stage of the preamp is biased for optimum noise, the second stage for optimum gain. ..
When power is applied to the circuit, the heater coil in the sensor is energized by the 5-V output of IC5, a 7805 voltage regulator. Breathing into the sensor with alcohol on your breath will lower the sensor"s resistance; consequently, the input voltage to the detector circuit, will change. The detector circuit consists of quad op amp, IC2 and its associated circuitry. All sections of the detector circuit are cahbrated via R3 and R4, and the inputs to each section are.....
This circuit uses two comparator pairs from an LM339N quad comparator; one pair drives the yellow positive (+)and negative (-)indicators, the other jointly drives the red warn LED3. The circuit draws its power from the unregulated portion of the power supply. The four comparators get their switching inputs from two parallel resistor-divider strings. Both~strings have their ends tied between the power supply"s positive and negative output terminals. ..
The circuit behaves like a zener diode over a large range of voltages. The current passing through the voltage divider R1-R2 is substantially larger than the transistor base current and is in the region of 8 mA. The stabilizing voltage is adjustable over the range 5-45 V by changing the value of R2. The total current drawn by the circuit is variable over the range 15 mA to 50 mA..
This circuit is useful in amateur radio VHF and UHF work where a mast-mounted antenna preamp is used for receiving. The kit controls T-R switching and change-over relay sequencing so that high RF levels are prevented ..
LDR1, a cadmium sulphide (CDS) photoresistive cell is used as the lower leg of a voltage divider between Vcc and ground. The timer terminals 2 and 6 are connected to the junction of the photocell and SENSITIVITY control Rl. The resistance of the photoresistive cell varies inversely as the light intensity; resistance is high when the illumination level is low; low in bright light. (The Radio Shack CDS cell 276-116 has a typically wide resistance range—about 3 megohms.....
This small circuit is a Linear amplifier for driving small UHF TV transmitters. Its gain is 7dB and can amplify a signal between 450-800 MHz. You can drive the circuit with 1 to 1,5 Watts signal. Better use double layer PCB with the second layer connected to earth. Use a stabilized power supply 25 volts and at least 5Amps...
As dusk begins to -fall, the sensor (a cadmium-sulfide light-dependent resistor or LDR) operates a small horn to provide an audible reminder that it's time to turn on your lights. To turn the circuit off—simply turn your headlights on and the noise stops. The base of Ql is fed through a voltage divider formed by R4, LDR1—a light-dependent resistor with an internal resistor of about 100 ohms under bright-light conditions and about 10 megohms in total.....
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