3-DIGIT LED COUNTER KIT
Two-board basic event counter. Main board has the 3-digit counter circuit while the second board has Count and Reset pushbutton switches and debounce circuit. Can be cascaded with other boards to provide more digits. Runs on 9V battery. 3.125" x 2" x 1".
Kit 1 $26.95

LCD TEMPERATURE METER KIT
(Celsius only.) Designed around a single IC that contains analog and digital sections to provide a simple yet versatile LCD meter. Other components convert the basic meter to read temperature (degrees C). With power switch. Runs on 9V battery. 3.75" x 2.25" x 0.75".
Kit 2 $29.95 DOCS - LCD Data - 7106 Data - 7106 App Note
 

LED DICE KIT
Uses seven red LED's to simulate the rolling of a die. Press then release the "Roll" button and the LED's slow down and stop. Based on the 555 timer and a counter IC. 9V battery clip. Operates from 4.5-15VDC. 3.125" x 2" x 0.5".
Kit 3 $15.95
 

Roulette LED
Electronic game. Ten LEDs in a circle. One LED is turned on at a time to simulate the spinning of a roulette ball around the wheel. Uses voltage controlled oscillator circuit. 'Ball' gradually slows down and stops on a number. 'Ball' speed can be adjusted. Uses 9V battery.
Kit 6 $15.95

POWER SUPPLY KIT
Basic circuit designed around two fixed TO-220 regulators. Provides a fixed output of +5V and a variable from +5 to 2V under the input voltage. Terminal strip output, solder pads and 3.5mm mini phone jack for input. 7-30VDC or 7-30VAC input. 3.125" x 2" x 1".
Kit 4 $18.75

3V FM Transmitter
The most powerful 'bug' available for its size, 3V supply and number of components. Guaranteed to transmit over 100 meters within buildings and to 500 meters in the open. Easily tunable in the FM band. Greater range at higher voltage and better aerial. Documentation.  For an excellent introduction to the theory of 'simple' 2 stage transmitters download FM Transmitter Theory 1.2MB
Kit 7 $9.95

LIGHT DETECTOR ALARM KIT
Circuit designed around a sensitive photo Darlington transistor and CMOS NAND gate. Circuit detects light and sounds an alarm buzzer. Useful as alarm in cash drawers, refrigerators, etc. Operates on 9VDC.
Kit 8 $8.95 each

MULTI-VIBRATOR BUILDING BLOCK KIT
Circuits demonstrate the action of the astable, monostable and bistable (flip-flop) multi-vibrator circuits. LED's provide visual indication of circuit action. Runs on 9V battery.  4" x 1.5" x 0.625".
Kit 9 $8.95 each DOCS

TOUCH SWITCH KIT
Low-voltage circuit designed to switch a relay. When used from 5-12VDC battery, a simple touch of a finger across two leads will control relay. Operates as a touch plate if DC power supply connected to AC line is used in place of battery. Relay rated 3A 115/130VAC. 2" x 2" x 1".
Kit 10 $12.95 each

LOW VOLTAGE FLASHER KIT
Circuit designed around the National LM3909 low-voltage flasher IC. Used to flash an LED or as a continuity tester. Two PC boards supplied. Runs on 1.5V DC. Single "D" cell will flash LED for two years. Solder pads for all connectors. 1.375" x 0.625" x 0.75".
Kit 11 $13.95 each

AUDIO TO LIGHT MODULATOR KIT
Designed around an opto-triac coupler and a power triac. 1.2-1.5V music signal drives the circuit. Triac rated 4A max @ 250VAC. Operates from 110 or 240VAC mains. Terminal strip for Load and AC. 3.5mm mini phone jack for audio input. 2.125" x 1.75" x 1".
Kit 12 $12.95 each

TAPE RECORDER VOX SWITCH KIT
When sound is detected, kit will turn on cassette recorder or other low-voltage load. Six-second turn-off delay allows for pauses in conversation. Requires recorder with "REMOTE" control jack. An external relay (not supplied) can be added to handle heavier line loads. 4.625" x 0.75" x 0.5".
Kit 13 $12.95 each

110V& 240V MAINS POWERED STROBE LIGHT
Kit contains Xenon Flashtube as found on aircraft, camera flash units, signal beacons and disco lights. Adjust to flash from 1 every three seconds to 3 flashes per second. CAUTION: Connects directly to mains power supply. Must be put in a suitable enclosed box before using. Two PCBs for different mains voltage.
Kit 14 $31.49 each

6- TO 12-VOLT PIEZO SCREAMER
Powerful 6V to 12V piezo alarm. Uses 556, autotransformer and two piezo alarm elements. Circuit will deliver over 110dB at 1 meter. Uses sweep circuit so there is no need to trim the circuit to match the cavity resonant frequency. We supply a plastic box with two piezo elements (35mm diameter) already mounted in their own resonant cavity. This is part of a commercial alarm unit but it uses our (better!) drive circuit. Ideal alarm unit for Kit 53 (Codepad/Burglar Alarm).
Kit 15   $15.59 each

FM Telephone Transmitter
Miniature transmitter which attaches in series with one of the two lines to your telephone. Transmits over 200 meters to an ordinary FM receiver. Transmits further if the FM receiver is near the phone line. Tune with ceramic trim cap. Uses the phone line as an aerial and power source. ZTX320 transistor specification.
Kit 16 $9.95

LOW VOLTAGE AMPLIFIER KIT
Circuit designed around the National LM386 IC, a variable gain audio amp. Use this kit as a building block for other projects. Operates on 4-12 VDC. Solder pads for all connections. 1.25" x 1.25" x 0.75".
Kit 17 $6.95 each

9V FM Transmitter
K18 PCB now has 5 pairs of SM pads for SM resistors to be supplied later. More powerful FM transmitter 'bug' than Kit 7. Tank oscillator coil built into the circuit board. Can be tuned anywhere in FM band. 9V battery operation. Over 400m range in the open depending on aerial used. • For an excellent introduction to the theory of 'simple' 2 stage transmitters download FM Transmitter Theory 1.2MB
Kit 18 $9.95

Crystal Locked Ultrasonic Movement Detector 1
Matched 40 kHz transmitter/receiver pair of transducers detects movement at over 7 meters. Separate PCB for mounting the active units. Latch/reset PCB-mounted switch on board. Sensitivity control. 9V battery operation. Transmitter is crystal- locked at 40kHz for maximum efficiency. Transducer Data
Kit 20 $35.95

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INTERCOM KIT

OP-AMP FUNCTION GENERATOR KIT
Circuit designed around a Quad Op-Amp connected as oscillator and wave shapers. Oscillator generates a square wave over 6Hz to 6KHz range. The other amps then produce the triangle and pseudo-sine outputs Solder pad outputs. Runs on 9V battery. 1.875" x 1.625" x 0.875".
Kit 23 $8.95 each

LOGIC PROBE KIT
Circuit examines the logic state in digital circuits. Three LED's provide visual indication and a piezo buzzer provides audio indication. Switch between TTL or CMOS logic. Runs on 5-15V DC supplied from equipment under test. Detects pulses >50nS.
Kit 24 $14.95 each

FIBEROPTIC AUDIO LINK KIT
Circuit designed around a matched fiber optic transmitter and receiver pair. Transmitter board uses microphone and IC to modulate an LED. Receiver board demodulates the light and drives the provided speaker. 14ft of plastic cable supplied but boards will drive up to 150M of cable. Runs on 2 9V batteries. Rec. 2" x 1.5" x 0.75". Transmitter 1.75" x 1.125" x 0.5".
Kit 26 $34.95 each

1 WATT AMPLIFIER KIT
Circuit designed around a single TDA7052 IC. Ideal part for larger projects. Drives 8 Ohm speaker (not supplied). Ideal for battery powered circuits. Operates on 3-15VDC. Solder pads for all connections. Only 1.75" x 1.125" x 0.875".
Kit 27 $7.95 each DOCS

Voice Activated FM Transmitter
A sound activated switch and an FM transmitter joined together to make a voice activated FM transmitter. Set the level of sound that it will respond to. Two stage transmitter needs tuning to get best results. Tuning Kit and instructions enclosed. Transmits up to 1 km in the open depending on the aerial used. ZTX320 transistor specification.
Kit 28 $12.95

COMBINATION LOCK KIT
Easy introduction to electronic locks. Two boards, one with 1-9 touch pads and connected to second board by 3-ft. cable. Second board has decoding ICs, matrix to set four number code, and relay to control external loads. Auto reset if wrong number entered. Runs on 9V battery. 3" x 2.5" x 1".
Kit 29 $18.95

PIR MOTION DETECTION KIT
State-of-the-art circuit uses motion sensing IC and a PC board mount plastic fresnel lens. Features include photocell for day light inactivation, single/dual pulse, sensitivity switch, adj. latch time red LED indicator with solder pad outputs to drive external circuits. Runs on 9V battery. 2.5" x 2" x 0.985".
Kit 30 $34.95 each DOCS

Three Stage FM Transmitter
Our most powerful FM 'bug' to date. A two stage FM transmitter with an RF transistor (ZTX320) in the output stage. 9V operation. On/off switch mounted on the PCB. • ZTX320 transistor specification. For an excellent introduction to the theory of 'simple' 2 and 3 stage transmitters download FM Transmitter Theory 1.2MB
Kit 32 $9.95