Input 1 is used as a gating period, during which a single rising edge on input 2 will cause a logic 1 output-any other number, indicating non-identical frequencies causes a logic 0 output. ICla converts input 1 to a narrow pulse which initializes IC2 which forms a two-stage shift register clocked by input 2. On the first edge of input 2 a logic 1 appears on the output of IC2b and for all subsequent inputs a logic 0 is present. At the end of the gating period this output is.....
This circuit uses the CA3207 sequence driver and CA3208 segment latch-driver in combination to drive display devices of up to 14 segments with up to 14 characters of display. ..
The circuit uses a four-bit latch (Ul). What makes the circuit sequential is that the set input of the first bit latch is tied..
A shows a COR/CAS circuit for repeater use. CR1 is a silicon diode. 2 may be any relay with a 12-V coil (a long-life..
You can use that circuit to drive a relay of 12 V with a trigering signal of 5V. It uses 2 diodes 1N4002, 1 transistor 2N3904 and two resistors...
The pseudorandom sequencer drives a solid-state relay. If you power a low-wattage lamp from the re..
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. ..
A 555 timer IC, operating in the one-shot mode, is triggered by light striking photoresistors. These normally have a resistance of several megohms but, in the presence of light, that resistance drops to several hundred ohms, permitting current from the six-volt source to flow in the circuit. The R-C combination shown gives an on-time of about two minutes. Photoresistors PC3 and PC4 are mounted at heatlight-height. When headlights illuminate the photoresistor, the timer.....
The sensing circuit rapidly disconnects the battery voltage and load whenever the voltage drops below a preset threshold. One-way operation prevents the circuit from reconnecting the load if the voltage should then rise above the threshold. Cl ensures that the circuit doesn"t activate while making connections to the battery; if you accidentally reverse these connections, Dl will block the turn on the relay. After you connect the battery, nothing happens until you.....
While the battery is being charged, its voltage is measured at V. If the measured voltage is lower than the minimum the relay will be energized, that wiU connect the charger circuit. When the battery voltage runs over the maximum set point, the relay is deenergized and it will be held that way until the voltage decreases below the minimum when it will be connected again. ..
Ql is used as an oscillator around 300 kHz. R9 is set so that the oscillator just begins to run. An object ne..
False alarms produced by semiconductor failure are impossible with this burglar-alarm circuit equipped with relays. What"s more, the circuit is virtually immune to false triggering. With a standby current of less than 0.1 mA, the circuit offers all the features an alarm needs: entry and exit delays, a timed alarm period, and automatic reset after an intrusion. One CMOS CD4093B quad NAND gate, IC1, supplies both logic and analog timing functions with the aid of.....
When the plate is touched, the gate input becomes low, changing the state of the latch. ..
At the heart of the whistle swatch are a pair of tone detectors, each of which is built around an LM567 tone decoder, which are supported by a minimum of additional components. This whistle switch is designed to respond to only two or more occurrences of a specific tone, or sequence of tones, within a specified period to prevent false triggering. Depending on the relay used, various ac loads can be controlled. Microphone MICl picks up the sound and U2 amplifies the signal.....
Ql and Q2 are general purpose transistors. The 10 K input pot is adjusted to a point just short of where Ql turns on as indicated by K pulling in. K is any 5 V reed relay. With the values shown for R (100 K) and C (47 µf), timing values from 5 to slightly over 5 seconds can be achieved..
IR radiation from LED2 (modulated by a 1-kHz wave) is keyed by Ul, and Ql is radiated. Reflected IR energy i..
This circuit is ideal for use as an over-under temperature monitor, where its dual output feature can be used to drive HIGH and LOW temperature-indicator lamps, relays, etc. Tl is a 6.3 volt filament transformer whose secondary winding is connected inside a four arm bridge. When the bridge is balanced, ac output is zero, and C5 (or C7) receives no gate signal. If the bridge is unbalanced by raising or lowering the thermistor's ambient temperature, and ac voltage will.....
Here's an effective little combination lock that you can put together in one evening's time. To open the lock, simply dial in the correct combination on the three rotary or thumbwheel switches. With the correct combination entered, current flows through Rl into Ql's gate terminal, causing the SCR to latch in a conductive state. This sends a current through relay Kl, which responds by closing its contacts and actuating whatever load is attached. After opening the lock,.....
When zero voltage switching is not required, methods of providing this function are illustrated. The lowest parts count version of a solid-state relay is an optoisolator, the triac driver HlU. Unfortunately, the ability of the Hll} to drive a load on a 60-Hz line is severely limited by its power dissipation and the dynamic characteristics of the detector. These factors limit applications to 30 -50 mA resistive loads on 120 Vac, and slightly higher values at lower.....
The electromagnetic ring launcher is comprised of.four subcircuits: a clock circuit (built around U5, a 555 oscillator/timer configured for astable operation), a count-down/display circuit (built around U3), a 74190 synchronous up/down counter with BCD outputs that is configured for countdown operation; U4, a ECG8368 BCD-to-7-segment latch/decoder/display driver; and DISP1, a common-cathode seven-segment display), a trigger circuit (comprised of U6), an MOC3010.....
Operational Amplifiers
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