Video Circuits

100s of Video circuits for every hobbyist, technician, student, and design professional. A nice reference tool which includes lots of Video circuits. Have a look at these circuit ideas, some of them may need some modification if they are to work as advertised. Ideas along with pretty good descriptions for each circuit.

Video Mixer	Modulator	Photo Flash
Video Wall circuits	Camera Circuits	Video Amplifier
TV Video Circuits	Television

Flash-meter

Insulated-gate, field-effect transistor (IGFET), Q2 and silicon photo cell Zl form the heart of this circuit. Transformer T1 is an audio-output type, but it"s reversed in the circuit. A sudden flash from a photoflash unit detected by Zl sends a voltage pulse through the low-impedance winding of Tl via Rl. That voltage pulse is stepped-up in Tl"s 500-!l, primary winding before being rectified by Ql. Transistor Ql is used as a diode; its emitter lead was snipped off.....

Rf-modulator

Because power MOSFETs offer high power gain at both audio and radio frequencies, they are useful in many areas of radio-circuit design. For rf applications, a MOSFET"s large safe operating area, V0 s vs ! 0, protects it against damage from reflected rf energy. As a modulator, a MOSFET"s transfer linearity aids fidelity. In the suppressed-carrier modulator, an rf signal is applied to the primary of transformer Tl, whose secondaries provide equal-amplitude,.....

Rgb-composite-converter

The incoming RGB inputs are terminated with resistors Rl, R2, and R3 and potentiometers RVl, RV2, and RV3. These provide input impedances of approximately 75 0. The presets should be adjusted to provide a maximum input of 1 V pk-pk into the MC1377. The inputs are ac-coupled into the encoder; the large value capacitor is required for the 60 Hz field component. The Colpitts oscillator for the color burst is formed around pins 17 and 18. About 0.5 V pk-pk should appear.....

Color-Bar Generator

IC5 generates RS-170 NTSC synch. IC1, IC2, and IC3 make up the red, green, and blue video signals that drive the video ..

Photo stop action

This circuit gives multiple "stop-action" photographic effects like showing a bouncing ball in up to nine locations in a single photograph. The circuit will automatically fire the bulbs sequentially with the time between each firing variable. The circuit is functionally complete except for the actual firing system. In many cases, a simple SCR will work, as shown. The firing can be initiated in one of two ways..

Color-tv-crosshatch-generator

This circuit provides a simple, low-cost crosshatch generator tor convergence and geometry adJUStments on color TVs. The generator is driven by two clocks, one for the horizontal drive, IC1ab, and one for the vertical drive, IC2ab. The clock outputs are applied to the two binary counters contained in IC5 which generate the line and field sync pulses and respective blanking periods. Line clock pulses, buffered by IC1c, are differentiated by C3/R5 to produce the vertical.....

Sound light-flash trigger

Sound input to the microphone triggers the IC monostable circuit which subsequently triggers an SCR, and hence the flash, after a time delay..

Xenon-flash-trigger

This circuit is used for remote photographic flash units that flash at the~ame time as the flash attached to the camera. This circuit is designed to the trigger cord or hot shoe connection of a commercial portable flash unit and triggers the unit from the light produced by the light of the flash unit attached to the camera. This provides remoteoperation without the need for wires or cables between the various units. The flash trigger unit should be connected to the.....

10F15-cascaded-video-mux

Two MAX455s can be cascaded to form a 1 of 15 video MUX by connecting the output of one MUX to one of the input channels of a second MUX. ..

Pulse-width-modulator

In this application, the timer is connected in the monostable mode. The circuit is triggered with a continuous pulse train and the threshold voltage is modulated by the signal applied to the control voltage terminal at pin 5. This has the effect of modulating the pulse width as the control voltage varies. ..

High-performance-video-switch

This figure shows a one-of-two switch with a sunnning amplifier. The video source"s line can be terminated either externally or internally to switch RO. With this termination resistor, a load change of less than 1 0 will be seen by the source when the switch changes state. For this reason, input isolation amplifiers are. not necessary. R4 can be varied to control circuit gain, but should never be less than 1400 0 since the NE5539 is internally compensated for gain.....

Summing-amplifier-clamping-circuit

This circuit is a traditional summing amplifier configuration with the addition of the de clamping circuit. The operation is quite simple; each component-synchronization, color burst, picture information, etc.of the composite video signal is applied to its own input terminal of the amplifier. These signals combine algebraically and form the composite signal at the output. ..

Photo Strobe Circuit

Sound or light sensors corniected to J2 produce a voltage that is amplified by ICl-a and ICl-b. A positive trigger voltage that is developed by D1 and 1)3 and amplified by ICl-d, drives 1C2 and 1C1 to trigger SCR1. SCR1 is connected to a strobe. ..

Video-pulse-amplifier

HA-5190 can drive the 75-0 coaxial cable with signals up to 2.5 V pk-pk without the need for current boosting. In this circuit, ..

Composite-video-signal-text-adder

This circuit shows a simple way to add text information to a composite-video signal that might be floating at some indeterminate de level. The text generator and composite-video source must have the same sync signal. The video-input and -output signals share the same terminal. C3 couples the video signal to the output of a rectifier circuit that is based on a subvideo-speed op amp. A faster op amp would clamp on individual sync pulses rather than on the video.....

Rf-modulator

Two IC rf modulators convert a suitable baseband video and audio signal up to a low VHF modulated carrier-Channel2 through 6 in the U.S., and 1 through 3 in japan-the LM1889 and the LM2889. Both !Cs are identical regarding the rf modulation function, including pin outs, and can provide either of two rf carriers with de switch selection of the desired carrier frequency. The LM1889 includes a crystal-controlled chroma subcarrier oscillator and balanced modulator for.....

Darkroom Timer Circuit

The electronic darkroom timer is built around a 555 oscillator/timer, a pair of general-purpose transistors, a buzzer, and an LED. The 555 (Ul) is configured as an astable multivibrator (free-running oscillator). The frequency of the oscillator is determined by the values through i3 and Cl through C4. Switch SI is used to divide the capacitor network to vary the time interval between beeps; when SI is closed, the circuit beeps at intervals of 30 seconds. With SI closed,.....

Sound trigger for flash unit

The circuit is based on operational amplifier IC1 used in the noninverting amplifier mode. Rl and 2 set the gain at about 500. RV1 (sensitivity) biases the noninverting input to the negative supply. Ql provides the relatively high trigger current required by the triac. When a signal is received by the microphone, the signals are amplified (by IC1). The triac is triggered and a low resistance appears across its Al and A2 terminals which are connected via the fiashlead to.....

TV modulator using a motorola MC1374

This one-chip modulator requires some outboard circuitry..

Enlarging Light Meter Circuit

Meter Ml, a +/-50-uA zero-center D`Arsonval meter movement is driven by Ul, a TL081 FET op amp, through R3. The gain of Ul is set at 11 by Rl and R2, while capacitor 01 is used to restrict the bandwidth of Ul to 1.6 Hz. Power for the circuit is derived from a simple dual-polarity 12- V power supply (consisting of Tl, D3, D4, 02, and 03). A light-dependent resistor (LDR), R16 (which is a semiconductor element whose resistance decreases as it is exposed to increasing.....