Page 5 New Circuits

Quick view of LED Digital Thermometer schematic

This digital thermometer with 7 LEDs on the temperature measured with a NTC. The circuit works by using an opamp, the known 741 that the voltage difference between its positive and negative input strengthened. This gain (sensitivity) can be set P2. With P1, the bridge of P1 and R1 be adjusted...

Hi-Low Logic Digital tester

Hi-Low Logic Digital tester

This tester, the logic level digital signals indicate on a 7-segment display. The display shows an H as the input signal is high. When the signal is low, the display shows an L on. If the input is open, the display shows N. The circuit consists of a TTL NAND IC type 74LS00 and three transistors. The NAND gates ensure that the right segments of the display can be controlled. ..

Digital counter circuit

Digital counter circuit

With this counter you can count laps for example (in conjunction with the Simple light trap ). The circuit uses two TTL ICs 74LSxx the series. The left IC is a decimaalteller. The input pulses 14 are counted and converted to the corresponding BCD code. This code is passed to the second IC, which is a code converter and display driver. Here the BCD code correct the display driver for LD1. ..

Automotive voltage tester schematic

Automotive voltage tester schematic

This is a simple spanniningszoeker that is very suitable for car, for connection of alarm systems, handsfree kits, radios, etc. At rest, the yellow LED because the path of least resistance. If the probe with a positive or negative pole connected is coming and the red or green and yellow LED light goes out. The yellow LED also serves as a check or put pressure on the circuit state...

Car Analog tachometer circuit

Car Analog tachometer circuit

This is a nice design for people who have no tachometer in the car or on the bike have. The circuit uses two ICs: an NE 555 and a CA 3140. The input of the circuit to the breaker of the motor (on the side that is not connected to ground). Thus, the ignition pulses within the circuit. By the two IC's, this signal then transformed into a speed-dependent voltage which is fed to the meter. The scale of the meter is 0 to 10 000 rpm. The circuit must be adjusted. For this, R6 IC2 temporarily disconnected. On R6 is a voltage of 4 V put. P2 is then adjusted so that the meter full scale deflection. ..

99 mV to 999 mV meter schematic

99 mV to 999 mV meter schematic

This circuit can for example be incorporated into a diet to pressure warning. The meter can measure voltages from -99 mV to 999 mV. The circuit uses two ICs, the CA 3161 and CA 3162. IC1 converts the analog signal into a digital signal. IC1 is also the multiplexed signal to T1-T3 can be controlled. The BCD code is then fed to IC1 IC2, a BCD/7-segments converter. Then the signal is fed to the displays. Pin 6 of IC1 (hold) can be used for a number of things. When pin 6 is grounded or open, the 4 Hz sampling frequency. When pin 6 is at 1.2 V, then enter the HOLD function is activated. ..

Toy Train rail detector circuit II

Toy Train rail detector circuit II

This circuit can detect whether a train in a particular drive. The output is TTL and CMOS compatible and can be processed by such a computer. The simple circuit works. The driving voltage is connected to the two terminals left. When the locomotive of the interrupted line is, the flow leading to the locomotive goes through the triac T1. This is then a voltage of about 1 V, which is conducting T3 or T4. Therefore, the LED D1 on and the output is logical zero. ..

Toy Train rail detector circuit

Toy Train rail detector circuit

This circuit must be used between the drive voltage of such a transformer and track. On JP1, the transformer is connected to JP2, the rails are connected to JP3, is a TTL "High" position when there is a tax on the trail is more of 2mA, but given the average LED more consumption, this should not be a problem. Works through a circuit voltage of 1.4 volts over the diodes, which are anti-parallel so that the circuit in both directions to use. ..

Extra security for radio controlled alarms

Extra security for radio controlled alarms

This is a small circuit that provides extra security for radio controlled models. When the signal from the transmitter fails, grab the circuit and set the servo connected to a preset position. The circuit is built around a CMOS IC, the 4093 with 4 Schmitt trigger NAND gates. IC1b and IC1c together a astabiele multivibrator, which generates pulses for the servo. When a transmitter signal does not and this is the input signal is available at the output...

9V LED light organ

9V LED light organ

This is a nice example circuit that can be used at parties. The four LEDs blink to the beat of the music. The light organ using a microphone responds to sound. T1 amplifies the signal from MIC. The sensitivity can be adjusted with P1. T4 controls the LEDs. These are preferably high intensity LEDs. ..

12V smooth Flashing circuit

12V smooth Flashing circuit

This circuit ensures that a blinking slowly, ie the lamp is brighter lights until a maximum is reached and then gradually decrease in strength until the lamp is off. IC1a opamp is used here to a triangular voltage generation. The opamp acts as a comparator, ie the output is at full power. If the positive input is higher than the minus input, the output of the opamp high and low otherwise. The resistor divider R1/R2 ensures that half the supply voltage to the positive input of the opamp state, but R3 is in parallel with R1 when the output is high, and parallel to R2 if the output is low. This input toggles between still 1 / 3 and 2 / 3 of the supply voltage. ..

LED Flasher IIV

LED Flasher IIV

This is a simple design of a single flashlight. This small circuit is within a half hour to build. The circuit operates from 4.5 to 12 V. Of course it is possible other than to drive an LED...

Triac mains light dimmer

Triac mains light dimmer

This is the schematic of the conventional light dimmer. L1 and C2, C3 form the lichtnetontstoring. In this circuit meets almost every TRIAC as a TIC226D. For C1, C2 and C3 good capacitors (MKT example) with a minimum operating voltage of 400V. ..

Electric candle simulation schematic

Electric candle simulation schematic

For a candle to burn, we need a heat source (the flame of a match) and to extinguish it, you do it just to blow out. The following circuit behaves similarly. If you use your fingers heats the thermistor, its resistance decreases. The tension on the thermistor is lower and there is more current to the base of the left transistor. From here, more power to the base of the right transistor, which will guide and the light comes on. If the light and the thermistor close to each other, the heat of the thermistor heat lamp and the lamp will remain lit. ..

Flashing Mains Lamps circuit

Flashing Mains Lamps circuit

This is a design for a flashlight that two 220 V alternating lights can control. The flashlight uses only one IC. IC1a IC1c to be used for the flashing signal generation. The output of IC1c thyristor T1 is controlled, it lights up then release L1. IC1c After the signal is again inverted so as L1 L2 lights not lit. ..