Ramsey UT5 User Manual

• Easy choice of Timer or

Oscillator operation.

• Makes ideal code practice
oscillator.

• Timer can be triggered by
positive or negative pulses.

• Runs on 5 - 15 VDC, drives up
to 100 mA. loads.

Solve all your timing needs easily and inexpensively. Timing from microseconds to hours, oscillation
from sub-audible to 100 KHz. Easy to use and apply kit features the popular 555 IC Timer chip with
fully detailed instruction manual and hook-ups!

UNIVERSAL

TIMER -

OSCILLATOR

Kit No. UT5

UT5 - 1

INTRODUCTION:

The purpose of the UT5 kit is to make the popular and versatile NE555 timer IC as convenient and understandable
to use as possible. Hundreds of 555 circuit ideas are around, but they all have one common need: a well-organized
circuit board for taking advantage of this economical IC's capabilities.

In addition, because of the many practical applications of the 555 IC, the UT5 Kit has proven to be an exceptionally
good educational resource for class and club projects as well as self-paced learning in electronics. For this reason,
this manual is prepared with beginners and students in mind.

Learners will appreciate the UT5 kit's combination of informative manual, useful printed circuit board, and basic
components for a small price. Experienced 555 IC users will welcome the practical and truly universal setup of the
PC board and might even review the useful 555 IC ideas offered in this booklet!

THE UT5 PC BOARD:

If you are going to put the 555 IC to work, you need something economical upon which to solder it - and to connect
up its many talents to the outside world. Even if you work out a 555 IC circuit on an experimental breadboard, a
permanent application requires some kind of final physical installation. Your alternative to this UT5 kit is to buy or
make a PC board, perf-board or some other ingenious and practical connections to the 8 pins of the tiny 555. If you
value your time, we know you'll appreciate the versatile organization of the UT- 5 PC board.

The versatility of the UT5 PC board is provided by:

• the in-out connections A,B,C,D,E and F

• mode configuration connections J1 and J2

• easy-access timing capacitor (C1) location.

• solder-points for various styles of potentiometers (R3)

UT5 - 2

THE 555 IC ITSELF:

The "555 timer chip," as it's popularly known among electronics hobbyists, packs over 40 parts, including 23
transistors, into its 8-pin package. It may be operated in either of two "modes" and the UT5 PC board is designed to
permit easy set-up of either mode:

Mono-Stable ("one shot") Mode: In this mode, the 555 awaits a command pulse to start a timing cycle which may be
any length you choose from miiliseconds to hours, depending on the value calculated for C1 and the setting of R3.

Astable Mode: This mode is most easily understood as "Oscillator Mode," which includes pulse generation, logic
clocks, LED flashing, as well as audio tone generation.

KIT ASSEMBLY PROCEDURE:

The UT5 is assembled and completed in three phases:
Phase 1: Soldering 555 IC and parts common to all circuits.

Phase 2: Planning and installing Timing and Mode components.
Phase 3: Planning and installing specific project connections.

The installation of the parts on the PC board does not take long and is not difficult. However, proper soldering and
correct selection of components is as important for this simple circuit as it is for our most complex kits.
First, check your parts against the Kit Parts List on the following page:

UT5 - 3

UT5: PARTS SUPPLIED WITH KIT:

A. PARTS COMMON TO ALL CIRCUIT APPLICATIONS:

 2 .01 uf disc capacitor (marked .01 or 103 or 10nf) (C2,C3)
 2 1K ohm resistor [brown-black-red] (R4,R5)
 2 10K ohm resistor [brown-black-orange] (R1,R2)
 1 100K to 250K ohm potentiometer (R3) [style may vary]
 1 NPN transistor (Q1) [2N3904 or equivalent]
 1 NE555 IC (U1) or equivalent [such as MC1455]

B. PARTS SUPPLIED FOR BASIC APPLICATIONS:

 1 1 uf electrolytic capacitor (C1-A)
 1 33 uf electrolytic capacitor (C1-B)
 1 .01 uf disc capacitor (marked .01 or 103 or 10nf) (C1-C)
 1 1K ohm resistor [brown-black-red] (R6 for astable mode)

C. REQUIRED, NOT SUPPLIED:

 5-15 volt DC power supply
 switching or keying controls


output device (relay, speaker, LED, transistor switch, etc.)

UT5 - 4

UT5 PARTS LAYOUT:

UT5 - 5

Phase 1: BASIC PC BOARD ASSEMBLY:



1. Install 10K resistor R1 [brown-black-orange].

 2. Install 10K resistor R2 [brown-black-orange].
 3. Install 1K resistor R4 [brown-black-red].
 4. Install 1K resistor R5 [brown-black-red].
 5. The 555 IC may be soldered directly to the PC board without worry, but you may use a 8-pin DIP socket (your

own) if you prefer. Use the same care in soldering such a socket and inserting the IC as you would in direct
soldering of the chip. Note that one end of the IC is marked by a dot, notch or band; this end MUST be oriented as
shown on the PC board layout.

 6. Install the 555 IC.
 7. Install C2, .01 uf (marked .01 or 103 or 10nf).
 8. Install NPN transistor Q1 with the flat side facing the nearest edge of the PC board (connection points C,D and

E).

 9. Install C3, .01 uf (marked .01 or 103 or 10nf).

This completes installation of all parts that remain constant for all UT5 applications, although R4 could be changed to
accommodate certain timing needs without replacing R3.

Phase 2: PLANNING TIMING AND MODE:



10. R3 may be the trimmer pot supplied or any potentiometer of your own choice. This control may be soldered
directly to the PC board, or to wires permitting panel mounting, etc.



11. After considering your intended application, install R3.

UT5 - 6