FREE CIRCUIT DIAGRAMS 4U: LED or Lamp Pulsar Circuit

Free Electronic Circuits,Schematic Diagram,Circuit Diagrams

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Electronic Circuit,Schematic Diagram,Circuit Diagrams

electronic circuit, circuit diagram, circuit schematic, schematic diagram, electronic diagram, audio, amplifier, power supply, guitar effect, current loop, current limiter, video, receiver, transmitter, transceiver, transistor, radio frequency, rf, active filters, digital, analog circuit, pwm, micro controller Free download

Saturday, September 05, 2009

LED or Lamp Pulsar Circuit

This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc. This operation mode is obtained by a triangular wave generator formed by two op-amps contained in a very cheap 8 pin DIL case IC. Q1 ensures current buffering, in order to obtain a better load drive. R4 & C1 are the timing components: using the values shown in the parts list, the total period is about 4 seconds.

Parts:

R1 = 4.7K
R2 = 4.7K
R3 = 22K
R4 = 2.2M
R5 = 10K
R6 = 47R
C1 = 1µF-63V
Q1 = BC337
D1 = Red Led
IC1 = LM358

Notes:

* The most satisfying results are obtained adopting for R4 a value ranging from 220K to 4M7. * Adopting for R4 a value below 220K, the pulsing effect will be indistinguishable from a normal blinking effect. * The LED can be any type and color. * You can use a filament lamp bulb instead of the LED, provided it is rated in the range 3.2 to 6V, 200mA max. * Using a bulb as a load, R6 must be omitted. * Voltage supply range can be 4 to 6V: 4.5V is the best compromise. * Do not supply the circuit with voltages exceeding 6V: it will work less good and Q1 could be damaged when a bulb will be used as the load. * At 6V supply, increase R6 value to 100 Ohm.