Strobe Light

Disco anyone? Actually, this strobe serves a much more useful purpose then making it look cool when you dance in the dark. You can use it to view fast moving objects, look for craks in PC boards (hold the strobe on the trace side of the board and look from the component side), and it is a great attention getter in a store window.

Parts

R1            1        10 Meg, 1/4 Watt Resistor
D1, D2      2       1N4003 Silicon Diode or 1N4007
C1, C2      2       10uF 350V Capacitor
C3            1         0.1uF 400 Volt Mylar Capacitor
T1             1        4KV Trigger Transformer (see "Notes")
FT             1       Flash Tube (see "Notes")
L1             1        Neon Bulb
Q1             1        106 SCR
S1             1        115V 1A SPST Switch
MISC         1        Case, Wire, Line Cord


Notes

1. This circuits is NOT isolated from ground. Use caution when operating without a case. A case is required for normal operation. Do not touch any part of the circuit with the case open or not installed.
2. Most any diodes rated at greater then 250 volts at 1 amp can be used instead of the 1N4003's.

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Black Light

This circuit is a simple ultraviolate light that can be powered by a 6 volt battery or power supply that is capable of supplying 1 or more amps.

C1	1	0.0047uf Mono Capacitor
C2	1	0.1uf Disc Capacitor
D1, D2	2	1N4007 Diode
FTB	1	Filtered Blacklight Tube
IC1	1	555 Timer IC
P1	1	10k Trim Pot
Q1	1	TIP30 PNP Power Transistor
R1	1	470 Ohm Resistor
R2	1	270 Ohm Resistor
T1	1	Medium Yellow Inverter Transformer
MISC	1	IC Socket, Heat Sink For Q1, Screw, Nut, Wire and PC Board

Notes:

1. P1 changes brightness of the black light tube.

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Electronic night light

Description
This circuit for an electronic night light was submitted by Adam from Canada. I have provided the notes.

     

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Notes

The two transistors are used as a direct coupled switch, Adam used 2SC711 but any general purpose transistor will do e.g. 2N3904, BC109C. The CDS photocell, type ORP12 is normally illuminated, therefore its resistance is low. The 50k control, the 1k resistor and the photocell form a potential divider which biases the first transistor. This transistor is on, its collector being held low, turns the last transistor and hence lamp and relay off.

In darkness, the resistance of the photocell becomes high and the first transistor switches off. The base voltage for the second transistor goes high, switching this transistor on and illuminating the lamp. Although Adam used a secondary supply of 3V , you could use any voltage and any lamp here. Make sure the relay contacts can handle the load. If using a large relay, it is preferable to wire a 1N4001 in reverse polarity across the coil. This will prevent the back EMF of the relay from damaging the transistors.

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TRIAC Light Dimmer

This little circuit can be used to dim lights up to about 350 watts. It uses a simple, standard TRIAC circuit that, in my expirience, generates very little heat. Please note that this circuit cannot be used with fluorescent lights.

Parts

R1       1        50k pot

R2       1        15k

C1       1        0.068 250v capacitor

C2       1        0.068 250v capacitor

L1        1        lamp to be controlled (up to 350 watts)

L2        1        neon lamp

TR1     1        40502  traic

Notes

1. This circuit is for 117VAC only. 220 or 240 V will burn up the circuit. L1 can be a maximum of 350 watts.

2. The circuit must be installed and used in a case.

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